The ability of Mega Diancie in Pokémon Omega Ruby and Alpha Sapphire is Magic Bounce.
The game Pokemon Omega Ruby and Alpha Sapphire has not yet been released. The game will be released in November. When the game comes out the ability of Primal Kyogre will known.
The new Mega Evolutions that premiere in Pokémon Omega Ruby and Pokémon Alpha Sapphire are Swampert, Sceptile, Latias, Latios, Rayquaza, Diancie, Beedrill, Pidgeot, Slowbro, Steelix, Sableye, Mawile, Sharpedo, Camerupt, Altaria, Glalie, Salamence, Metagross, Lopunny, Gallade and Audino which officially adds up to a total of 46 species being capable of Mega Evolution and there are 48 Mega Evolutions overall as of Pokémon Omega Ruby and Alpha Sapphire's release.
There is no roller skate item in Alpha Sapphire.
Mega Swampert has the ability Swift Swim, which doubles its Speed stat in Rain.
From October 27 to November 16, 2014 you can obtain a free download code for the Mythical Pokemon Diancie for Pokemon X and Y. If this event Diancie is then transferred to the upcoming Omega Ruby and Alpha Sapphire then another event will occur where players can obtain Diancie's Mega Stone.
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.