You can find Eevee on route 116. You have to use the DexNav before you can encounter it. It's rarity is uncommon and it will have level 8.
No, you will need to trade for them or transfer them via Pokemon Bank to get them 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.
There is no roller skate item in Alpha Sapphire.
Nowhere.
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.
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.
Magikarp
Yes, Tm's in Pokemon Omega Ruby and Alpha Sapphire are re-useable
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.
In Pokemon Omega Ruby, Latios can be found in Southern Island after obtaining the HM Surf and going to Route 123. To find Latias, you will need to get the Eon Ticket to fly to Southern Island to get her. Pokemon Alpha Sapphire has the same methods, but with the opposite Pokemon.
No