There is no roller skate item in Alpha Sapphire.
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.
Yes, Tm's in Pokemon Omega Ruby and Alpha Sapphire are re-useable
No, Zubat cannot learn Flash.
The ability of Mega Diancie in Pokémon Omega Ruby and Alpha Sapphire is Magic Bounce.
The following Pokemon that you can easily get to learn Flash in Sapphire: Beautifly or Dustox Lotad or Lombre Oddish Gloom
You can catch Torkoal in Pokemon Omega Ruby and Alpha Sapphire when the black smoke and the fire dies down.
Sapphire is a form of aluminum oxide - alpha Al2O3.
You cannot get Flash Cannon in Sapphire, it was a new move made for Diamond, Pearl and above. It wasn't made when Sapphire, Ruby, Emerald, Leaf Green or Fire Red came out.
No, you will need to trade for them or transfer them via Pokemon Bank to get them in Pokemon Omega Ruby and Alpha Sapphire.