"So nice of you to join us." Lumiere says to Ubogri. "It appears you followed in the way we did. No, the gargoyle seemed to be completely inanimate right now, but there were cavities upon its attached arms, so it may not be the last time we experience that statue." She then looks to the other spheres on the walls. "We have determined there are illusions over the spheres, and conjuration over the archway. Jerigg here has thankfully determined that the crimson and black spheres appear to be hollow as well."

You crawl after Falmo after picking the hand. It's a small passage but you manage to squeeze while Falmo's hidden. You as well notice your two lost companions.

Ubogri simply nods at the human, standing with his arms crossed, looking about the room casually.

Falmo will silently walk up behind the two of them and say, "I agree.  Black is our best bet.  We ran into an animate version of that back off of the first hallway, so it seems reasonable that it would happen again."

(Can I say that I investigated the gargoyle as well?)

If so, 23 or 17

Falmo would be looking for any secrets hidden on it, not necessarily whether it’s alive or not.

In addition, Falmo will fade back into the shadows (32 or 25) and then Ready an arrow for any enemy that might appear after activating the sphere.

You go back trough the crawlspace to check the gargoyle and you see that the open and outstretched hands of the statue have some carved depressions big enough for a gem to fit. The fallen arm doesn't seem to have one. Then you come back into the main hall readying your arrow. 

I cast light on three ballbearings and throw one down each of the openings and one into the arch.

You toss the bearings into the openings and you see that the one behind the black circle turns right after a bit, the one behind the red circle goes instead straight. Then you toss a bearing into the mist; it disappears from your sight into the mist, but you hear the sound of it hitting the wall behind.

Ubogri begrudgingly approaches, looking where the three ball bearings had been tossed. Looking again at the end of the corridor, the half-orc asks almost as if trying to not be overheard, "What's through the archway? I assume you've checked it and the doors," he says, motioning with his head back toward the two doors.

"Not yet. I do not think going through another misty archway until we have expended all other paths is best." Lumiere comments. "I shall try the red orb first. If you could hold this rope while I attempt to pass through."

Ubogri takes the end of the rope, looking surprised for a second.

I wait to see what happens.

Lumiere will take her shortsword and carefully place it through the red sphere first, trying to gauge the openness behind the illusion before entering.

You stick the sword into the red circle and you manage to determine that the size of the passage is big enough for you to crawl inside.

Lumiere will place her left foot into the crawl space first, testing as she'd rather lose her leg than her head to a trap. Once she is satisfied she can crawl in head-first, she'll begin to head through, using her lantern of revealing to illuminate her path.

After getting sure it's safe to go in you start to crawl into the passage with the light of your lantern illuminating the muddy walls around you. It takes you a minute or so but after the small tunnel turns right you reach a solid stone wall and what looks to be a dead end.

Lumiere does a quick double check before crawling back to the others.

Investigation: 7
Perception: 21

You notice nothing strange in the wall ahead so you take your stuff and start crawling back into the sphere's hallway. 

"It appears to be a dead end." Lumiere comments to the others. "Let us try the black hole next, as it is the one that I believe suits the rhyme."