It can be fun to experiment with. I used to have 2 Chinese V30s and 2 K100s in my first Bogner cab. I never loved it though. V30 mixed with G12T75 is really popular.
Mixing a V30 with an alnico blue is something I've never heard of. Those are quite different. Bear in mind that you still need to match impedance and your total power handling will be your lowest speaker's max times the number of speakers. In your case, 15 X 2 = 30 watts.