i think it is in mount pyre (sorry i cant guarantee it)
There is not a tm for bite or crunch.
Thunderbolt
Yes, Tm's in Pokemon Omega Ruby and Alpha Sapphire are re-useable
Trade.
Double Team
you can get it in seafloor cavern
25
at the game corner
In the Safari Zone
It is located at Meteor Falls
double team
Location is Route 115