Very nice Bob.
I particularly like the 'Anthropologist ' . I'll also give a nod to the 'Astronomers' glasses. A very subtle detail that takes years of clay pushing to know when you can play with an under cut,(and get away with it.)
Your 'Academica' is full of character. Im just wonderinghow I'd use it as I've already a 'Mr Porter' school master floating around with an almost identical pose ,only mirroring yours.
You'll have to forgive my ignorance or rather the lack of lateral thinking ( burning the midnight oil at the moment. ) But I can't quite place your inspiration for the forth figure.
Waffling aside . There's not much I buy these days as just as easy to make what I need.But these will be on that meagre list.
Mark