[Fyron]

As one who had just started to use FQM, I guess the question would be asked which mods can't use FQM?

That depends on which FQM you are talking about, really. Maps generated with FQM Standard can be used with all non-quadrant mods except for Devnull Mod. But, Devnull has an earlier Version of FQM Standard built into it, so this is not too much of a loss. Proportions can be a bad mod to use a FQM map in because of the asteroid fields. Remote mining the large number of asteroids gives you a lot of resources that you are not supposed to have in Proportions, and takes away many special Proportions aspects. The maps will indeed work, but it could be problematic.

FQM Deluxe has to be manually combined with other mods to work with them, as per the instructions in it's help folder (or on the FQM web site). It should work fine with nearly any mod out there (other than mods that make extensive changes to planetsizes.txt and secttypes.txt, but most mods don't do that).