I realise now that i might have picked the wrong characters for some skills. For example, my knight doesn't need 30 Charisma other than to get master skill level in Merchant. My question is, is it possible to use stat boosting artifacts in order to "trick" the teachers into teaching you?

I don't have enough personality boosting artifacts to give this a try yet and just wanted to see if it was worth the effort.

Yes it is. Also spells should work too.

Thanks! It worked great.