You can change Rotom's Form by interacting with the cardboard boxes in Professor Birch's laboratory on the bottom right corner. This will also give Rotom a new move as you change its form to what you want it to be.
No, you will need to trade for them or transfer them via Pokemon Bank to get them in Pokemon Omega Ruby and Alpha Sapphire.
No, there are no roms for Pokemon Omega Ruby and Alpha Sapphire currently nor a working 3DS emulator. (They are also incompatible with the Desmume emulator.)
You have to transfer it from your Pokewalker. You get it on Icy Mtn. Road.
It evolves by happiness
You can get two ferry tickets:The ticket for the SS Tidal is obtained by completing the Delta Episode.You can get the Eon ticket by Streetpassing someone with Pokemon Alpha Sapphire or Omega Ruby.
There is no roller skate item in Alpha Sapphire.
Actually Pokemon Omega Ruby and Alpha Sapphire is not out yet, but I strongly believe Bulbasaur will evolve at level as usual I doubt it would change dramatically.
You can catch Skitty in Pokemon Omega Ruby and Alpha Sapphire in the barks of trees.
You battle Kyogre for your chance to capture it in Pokemon Alpha Sapphire after you capture the groudon.
Magikarp
Yes, Tm's in Pokemon Omega Ruby and Alpha Sapphire are re-useable
No, you will need to trade for them or transfer them via Pokemon Bank to get them in Pokemon Omega Ruby and Alpha Sapphire.
Houndour can be obtained by trading from Pokemon X or Y. It cannot be caught in the wild in Pokemon Omega Ruby and Alpha Sapphire.
You will need to trade for Weedle or breed Kakuna. Kakuna can be found only in the Safari Zone in Pokemon Alpha Sapphire and Omega Ruby.
No
It is not yet known if there is a building location for the GTS in Pokemon Omega Ruby and Alpha Sapphire.
Yes, all the TMs that were in Pokemon X and Y will be available as TMs in Pokemon Omega Ruby and Alpha Sapphire.