2. Don't get caught up on the name, it is not required that all planets were once liquid, merely that they deform under their own gravity. The amount of force a rock can withstand to hold it's shape is basically a constant for a given shape. Gravity is a force that isn't a constant, it can increase via accumulation of mass and eventually exceed the strength of any given rock. When that happens the rock deforms until its new shape can withstand the pressure and there is a state of equilibrium. The type of deformation can be elastic, plastic or fracture depending on the exact circumstances. For elastic or plastic deformation the rock will bend* or squash into a new shape. If fracture occurs the rock will be breaking down into smaller components which will form a more rounded shape. Either way, it's perfectly fine to use a concept from fluid mechanics for a solid that can't maintain it's shape.
You aren't accurate here. If a rock is not elastic or plastic, then applying gravity will not change that. It is heat energy that will cause the rock molecules to loosen and allow deformation to the measure of the heat content for a particular crystalline shape. So, your notion that a solid planet can get so large that its own gravity will deform can't occur unless the pressure translates to heat. The point being that the only way a clump of matter became spherical is due to heat causing enough melting to allow a material to, like water, seek its own level. Then, because there is a center of gravity and sphere results. The problem with a simplistic notion of, "hey, lets throw some rock together, let them melt and form a sphere is that the materials of the melt will not only seek a equal level, but, also the diverse materials will seperate into distinct levels. Which raises a problem in that the earth doesn't show any such proper layering as would correspond to having been so hot as to allow layering. We are faced with many problems which are being ignored because the fake consensus science forbids truth in favor of retaining an anti-biblical-God recognition of natural reality. The reason a common sense man believes there is a creator God is not because, he has seen him, wants him, or understands him, but, because by strict rigorous logic there simply is no other possibility. This is why all the bogus science theories end up sharing the trait of resorting to "probability and chance" to kick start, and maintain some vague sense of making sense. Relying on chance to any degree is actually a admission of ignorance to nth degree and thus, is the hallmark of non sciences like, magic. The modern mythical theories of origins require all men to ignore straightforward proofs of the stupidity of many of the notions. That is why consensus is required to bar the door, and that, along with presentations of supposedly charismatic, cultic personalities.
*I know some creationists like to claim that rock can't bend in order to say that uncracked folded rock layers were created by a flood. Rock will deform under pressure and/or heat just like any other solid. Look up plastic deformation if you need further details.
Are you actually not aware that rocks don't bend because of rigidity? That for a rock to bend it is its rigidity that must be changed or otherwise the rigid rock will snap before it bends. Of course, I'm not talking about an imperceptible bending, since, all solid things are measurably somewhat rigid, malleable, ductile etc. If I take a cigarette, I can tie that cigarette into a knot. But, to do so it's boundaries must be constrained, and so I wrap the cigarette in it's package cellophane, tightly and then I can bend it. When we see many layers, or one layer, of solid rock bent into sinusoidal waveforms, we know that gravity didn't cause it because gravity gravitates all length of the layers equally towards the center. Thus, we see that horizontal force of compression will fold multi or single layer strats into sinusoidal forms. But, only if the layers are heated, wet, or both. Otherwise materials science proves that rigid materials when compressed will snap, and shatter. On the earth we see both forms of results of compression. We see sharp mountain peaks and we see soft rolling layers. Some mountain peaks rose straight upward most probably due to horizontal pressure converted to vertical uplift due to a triangular wedge beneath the mountain driving the mountain upwards as the horizontal compression wave forces lateral masses against the wedge. In other places we see that formerly flat sheet remained rigid under great horizontal compression and snapped upwards and forced over other layers into the sky at various angles. I brought up a point about the moon that is being, not ignored, but avoided. First, a hard surface moon struck by random meteors should exhibit random angles of attack, but, curiously and notably the moon exhibits its craters as though struck perfectly head on towards the center. And, the glancing blows are not seen, the horizontal gouging etc. If the moon were molten and meteors landed then, the moon would absorb those rocky projectiles and no mark on the surface of the moon would reveal what had occurred. If the moon were soft but, not molten, or a liquid, but elastic, then a meteor could strike it and cause some of the craters we see if the meteor struck at the right moment of plasticity of the surface. This is seen is cooling clay or muds. That is, in boiling muds when bubbles of mud collapse, and in time lapsed photos of liquid events where a object fell into the liquid we see the shape of craters formed. And the rebound structure notable in the center of craters is understandable because of the springiness due to the tension response of a semi-solid material rebounding back upwards after a downward strike. These shapes explain the forms of the moon's craters, but, the problem is, that the moon must be hot, and plastic, and it must be cooling so very rapidly as to no allow the time necessary to return fully to surface level. But, the visual evidence presents that as the situation for many of the crater forms on the moon and other moons and planets. That a very hot planet was snap frozen soon after bombardment. But, if we suppose the moon was that hot, then we can't suppose water on the moon since water would have boiled away into space long before sufficient cooling allowed it fall back as ice. It is logical to suppose that any water found on the moon came from the earth which has so much. And this also points to how if one invented a story where water arrives from the great beyond in buckets of some kind (meteors) then the moon should exhibit a tremendous amount of water as well, which it doesn't. So, if we reject the notion that water came to the moon from the earth, then we are forced to suppose the moon arrived, long after the water of the earths seas arrived. Again, whenever men resort to, answers like, "water came here from somewhere else" "rocks came here from somewhere else" "elements came here from somewhere else" "life came here from somewhere else" ...long ago...then the scientific thinker is forced to admit that such men have no clue where anything came from, nor how, and are simply shoving such problems of origin off into the unknown. That is, they are free to believe themselves right, but, they are lying if they pretense such answers are scientific. Me, I think when God said "Let there be light" that all matter in our cosmos was lit. That means energy liberation. And that means heat and warmth, and an opprotunity to clump matter into large sources of heat, and to shape planets shperically, with each planet having given a unique material composition. Which although the modern fake science folk will scoff about as though they have proof that God didn't do as he said in Genesis. But, what I like to point out, is that the uniqueness of each planet is strange, and proves that none of them came from the same place. The diversity of the planets is by design of God who knows what wise men must end up reasoning about them. That, diversity arises from a creative creator with power. Diversity cannot arise naturally because there is no law of diversity. And there is no law of seperation of diverse things accomplished in cold dead darkness. If I find a seam of gold the question is how does gold get pooled into one place? If a gold meteor delivered the gold and it hit a hard surface the gold would vaporize and disperse finely everywhere. If the gold struck a soft surface it would strike deep to where it is hot and could melt and dissipate away in strands to become seams. But, if the molten rock it entered is that hot then when cooling occurred later the gold should have fell to the center of the earth with the uranium and other heavy elements. The point is this, no one can tell an straightforward scientic story of how life, nor inorganic structures formed themselves without a creative creator with design in mind. It's not an intelligent way to spend the few days of one's life on earth trying to imagine how no body did nothing and yet all things turned out so nicely as to allow me a wasted life time. The water on the moon probably got there during the catastrophy of the Deluge told of in the book of Genesis. One thing to keep in mind when confronting a biased,consensus science, systematic, political machine, is that when the mythmakers want to go to Mars to try and prove they can escape the earth where God put man for a short time, they will lie about there being water out in space, on the moon, on Mars or somewhere on the way, because they haven't completely lost their minds, and know that the math says, mankind is not going anywhere without water and its to heavy to ship from the surface of the earth, so lets tell the common folk that its already out there waiting on us. It's a sad, sad situation modern man is in, globally as men face the end of the world predicted by God in his holy Book the Bible.