Loremaster - could be found in any scholastically inclined area. Meistersinger - these are definitive elven bards. Skald - The Northern Reaches, Eusdria, Klantyre, the Heldannic Territories. Seems that the idea of actors and theatre is a Thyatian thing in Mystara. So that's where I would expect Thespians to be found.
Elves can be bards however.
I think the idea of the Minstrel is that its a bard who plays music more as a form of art - a grey elven sort of thing. Really, this stuff is all off the top of my head. I was disappointed to see Emilio in KKoA being 0 level human.