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 will be three new evolutions in Pokemon Omega Ruby/Alpha Sapphire. They are for Sceptile, Swampert, and Diancie. The evolutions will be triggered by using the Mega Bangle item.
You can catch Skitty in Pokemon Omega Ruby and Alpha Sapphire in the barks of trees.
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.
These Pokemon can be found before the National Dex: Latias (Alpha Sapphire), Latios (Omega Ruby), Kyogre (Alpha Sapphire), Groudon (Omega Ruby), Regirock, Regice, and Registeel. These Pokemon can only be obtained in the Delta Episode: Rayquaza and Deoxys. Post-National Dex Legendary Pokemon are: Regigigas, Ho-Oh (Omega Ruby), Lugia (Alpha Sapphire), Heatran, Mesprit, Uxie, Axelf, Palkia (Omega Ruby), Dialga (Alpha Sapphire), Giratina, Cobalion, Terrakion, Virizion, Reshiram (Omega Ruby), Zekrom (Alpha Sapphire), Kyurem, Raikou, Entei, Suicune, Tornadus (Omega Ruby), Thundurus (Alpha Sapphire), Landorus, and Cresselia.
No
It is not yet known if there is a building location for the GTS in Pokemon Omega Ruby and Alpha Sapphire.
The ability of Mega Diancie in Pokémon Omega Ruby and Alpha Sapphire is Magic Bounce.
Yes, all the TMs that were in Pokemon X and Y will be available as TMs 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.)
all of them
There is none
No. Pokemon Omega Ruby and Alpha Saphire are remakes of Ruby and Sapphire, from 3rd Gen. Omega Ruby and Alpha Sapphire are in the same generation as X and Y, 6. Hope this helps you.^w^