I think so you need to wait for a swam of them they are quite rare swarm's though. Good luck.

This is not possible without a cheat. I can't say any more because there is no more. Trade or cheat are your two option's.

Plus it is the same in dimond too and I don't have the game but I think you get it underground.

Steelix a steel cloak I think it is called to evolve from onix. Dusknoir it needs a erm I tink it's a reper cloth. Erm I can not think of any more but I will come back when I think of some more ok?