Pretty interesting idea here, turning match-3 into a competitive turn-based duelling game. I like how you've given each character a "playstyle" by forcing them into using specific resources as well. I'd be interested to see what this game grows into, if you're still working on it. I've got just 1 criticism:
Since there aren't a lot of spells for each class and each class is limited to using spells of certain types, the spellpool doesn't feel like it adds much to the gameplay. You'll need to either add a lot more spells for each class, or make it so that each spell a player gets disappears after a certain number of uses, so that they have to continue buying them. Considering "Strike" is in the spellpool (which currently makes no sense since that's the default spell players always have from the beginning), I recommend the latter, but adding some more spells would definitely be a plus too.
I've got some ideas for spells:
Injure/Intimidate (name depends on what class you give the spell to): Remove 1 of your opponent's apprentices until the end of your next turn.
Cloak (illusionist spell): Select 1... you call the resources you're trying to match "gems", I believe? Anyway, the "gem" you select can't be moved by your opponent during their next turn, and can't be matched until your next turn.
Goldcasting (merchant spell): During the turn you use this spell, whenever you cast any other spells afterward, you can use gold and merchants as substitutes for whatever resources and apprentices would normally be required to cast the spell.