You can use as many of the same or different CMFs as you want. The idea is to expand on the collectible minifig series and either create what a set would be for that fig, or at least a MOC diorama of sorts that fits with the CMF’s theme.
Great idea. The possibilities are virtually endless. I’ve been working on some concept ideas for The Prancing Pony from The Fellowship of the Ring. Here is a weary knight (Series 9) heading to his favorite inn for the evening.