@sphereii
Since mods that use the same xml's conflict with one another, then it's safe to say that mods that don't touch the same xml's don't conflict. Since your launcher seems to know what it's grabbing anyway (yes, this is the big presumption, I know), maybe you could add a feature that does, say, if you click on valmod, the other mods that would be compatible in the list turn blue or something?
Click on valmod, and Compo and Dying Lands goes blue indicating it's compatible, and of course when you click Dying Lands then Compo goes back to regular because it's not compatible with Dying Lands.