There is not a tm for bite or crunch.
Yes, Tm's in Pokemon Omega Ruby and Alpha Sapphire are re-useable
Thunderbolt
You have to give it the TM. (Which can be bought at the department store in Lilycove city) Hope I helped! :)
Double Team
Trade.
you can get it in seafloor cavern
25
at the game corner
In the Safari Zone
It is located at Meteor Falls
double team