Fits with the minion rules!
Depends - eg for a ghoul pack I bought 6. For soldiers, 8 or 10 is good for a squad. Sky Reavers I got 8; Doomguard 6.
I buy minis in the following numbers (when possible): 1, 2, 3, 4, 6, 8, 12, or 16.
(And yes, there are times when I will use all 16 minis...
