I've personally tried the Irrlicht Scene format and it does not work. So I'm suspicious of this list.
Many of these are model formats, not world formats. From experience again, Firefly only partially supports them: just as once example, it only loads the first object found in a FBX or X file (can't remember which), not the entire object tree, so that format was useless for worlds.
It does seem to import many FBX character models just fine, in the Animated Mesh object.
Quake level editors are also basically a non-starter because of their intensely game-specific configuration. This is another format I've also personally tried to get working and been unable to.
The bottom line is that Firefly has no actually fully supported world editor with a complete tutorial. If there is a format it happens to fully support, it's hard to find. So this is still a problem in my opinion.
I've only tried importing models before, was hoping to wait for updates before actually creating a game in it, but seems it's just dead now. A shame since Firefly could've been a cool way to create Dungeon crawlers and more, nothing fancy (unless you baked in high quality textures with amazing lighting for visuals).
It's a shame, you pay something 1 years later dead, and then new dlc out you pay it boom dead and again...
Oh well, what I'm working on is 2D atm, 3D is something I'm doing in Unreal but 3D in Firefly had its charm (Ogre engine?) so that's why bought the DLC.
Don't really care much for third party (PAID) editors. Firefly needs a better editor from Clickteam, else it's dead (which it is).