Another brainbuster. Caused quite an argument at my local Pokemon League.
Say I use a Pokemon Breeder to evolve my Squirtle into Blastoise. Then, later
on in the game, I play a Devolution Spray. Does my Blastoise go all the way
back to a Squirtle, or what?

Absolutely.  It goes to whatever the card right below it is.  If you Bred it, then it goes to Squirtle.

Scott