1: I don't think there are. People have Skittys instead of cats, and get their milk from Miltanks, so I'm like 90% sure pokemon simply ARE the animals of that world.
2. I don't think they can catch people, but some inanimate objects seem to be able to. Satoshi (Ash) once 'caught' a riceball.
3. If my assumption on question number one is correct, then I would also assume that they do eat eachother. You may think of it as gruesome, but that's the reality of our world and we don't bat an eyelash. But then, pokemon are significantly more intelligent than the animals of the real world, so it's POSSIBLE that they simply live off the berries in the wild, though this doesn't seem likely to me.
4. I really can't think of an explanation for evolution. The closest I can come up with is essentially the explanation for Trance in Final Fantasy IX-it is brought on by a surge of emotion due to the need to be stronger and survive. This is also essentially the reason species in the real world, including human beings, evolve, though at a much slower pace, obviously.
5. Some of the new pokemon do look kind of lame, but let's face it, the pokemon industry is one of the huge draws on anime and gaming economy from children, and even some adults (admittedly, such as myself). I don't think it will ever truly end until they are so badly out of ideas that they produce a game that next to no one buys.
6. My theory is that becoming a pokemon trainer and striking out on your own is viewed as a right of passage in the pokemon world, like a boy's first hunt in Native American and African tribes, or the right to drive for teens in US and other metropolitan countries. As you grow up, you are expected to take on more responsibilities and be able to take care of yourself, as well as gaining more privileges.
7. It's possible that they just never felt the need to focus on the schooling system, other than the pokemon school since it is essential to the point of the series. If not, maybe the society of the pokemon world is like in the old days-parents are expected to be responsible for their children's education, and all the children are homeschooled.
8. The idea of a pokemon traveling outside its ball was not introduced until the anime was released, and therefore was used in the Yellow Game, which was based largely on the events of the anime. And for a good part of the series, Satoshi's Pikachu was the only pokemon seen doing so. Probably the reason they finally brought the function into HeartGold and SoulSilver, is due to the fact that the series started bringing it in so much more, ie. Kasumi's (Misty's) Togepi, Hikari's (Dawn's) Piplup.