I'm no scientist, but I've some general knowledge, and I'll try to answer this with the best I can.
1) Nobody knows. That's the huge question mark. I think that some theory is that time didn't existed before the Big-Bang, and as such the question "how long did it existed before ?" has no meaning.
2) Nobody knows. Part of the previous question mark.
3) That is easy to answer. Matter as we know it, is nearly entirely empty, to a point it's frightening.
The distance between atoms, is large. Even in dense formation (like stone), they are quite distant from each other.
The void inside atoms, is simply indredible. If the nucleus was a tennis ball, the electron would be roughly at the distance of the sun (or the moon, I don't remember). Just imagine how many tennis ball you can put into such a sphere, and you can imagine how much you can compress matter.
Even further, the protons/neutrons themselves, are formed of void in equivalent proportions as atoms. And so on.
So you can safely assume we can compress the whole universe into something tiny without problem. Matter is totally empty ^^
4) There is plenty of little hints, which are extremely theoricals, and based on deductions and theories. They also observe the "residual glow" (or something like that), the fact that the temperature of the universe is 3 °K, and not the absolute zero. And they apply to the universe the tools they found by observing and testing matter in strange condition (particules accelerators and so on).
5) Yes, several. Breeding is an easy example (whole races of dogs have been created).
Study of human physiology has also showed evolutive trends (tiny, of course, as humans endure extremely little natural selection, due to them being on the absolute top of the ladder). There is also the chemical-resistant vermins that appear as we use insecticides, and samely the antiobiotic-resistant bacterias.
6) Many times. The problem is, there is ALWAYS a "missing link", because each time another one is found, the question "then, between this one and now, there is a missing link !". Each fossil is a "missing link" by itself, between two state of evolution.
7) If your genes change, you change. That's as simple as that. Micro-evolution is tiny changes in the DNA. Macro-evolution is simply when the accumulated changes in this DNA, shows on the surface and actually change something noticeable in the creature compared to a distinct enough predecessor.
8) Every single being in existance is a transition between one specie and another.
This question shows a lack of understanding in what is evolution.
"species" aren't fixed states, that some creatures jump from one to another in some generations.
"species" are a set of caracteristics, which are shared in sufficient quantity by creatures to let them reproduce between themselves.
Each single life bring a change to the DNA of its children. Sometimes, this change does nothing, sometimes, it reverts a previous change, sometimes, it hamper the child, sometimes it boosts it. When these changes are numerous enough, you can say that there is another specie. It doesn't necessarily mean that the "previous" specie has disappeared. It's possible that only a little group of the previous species, living in a different environment, has changed.
The result is that now, this group can't reproduce with the previous species, and as such, reproduce only between itself. It's a new species.
Each individual in it bring changes to its children. See above and repeat.
