Me and my brother tried this, me on CNJ 22 and he was PUG 18, we both have very bad gear. We could take on several mobs at a time, but in some rooms there were just too many and they respawned too fast so we ended up just running through them until the mobs deaggrod. It worked well and we got to the crab NM without any issues and we duod him without any problems at all.
After that we decided to try to get to the Remora, we again ran through the parts we couldn't clear and found him. We didn't know what to expect with this one so we kind of just went with it. All the little remora was with him and my brother could not hold hate so I ended up tanking pretty quickly. My brother focused on the small mobs first, but he didn't do much dmg to them and I ended up dying pretty fast with all but 1 little mob on me. We didn't know the little ones were a part of the NM until we pulled him nor that they would require so much dmg to take down. I think if we try him duo again he will have to focus the main remora while I try to take care of the adds. Really though I think we will just try to bring one more who can help out with the small ones.
Either way, it was SUPER FUN! :)
Respawns are too quick in general, the same issue happens doing beastman strongholds with smaller groups. Global respawn timer is like 60 seconds tops, so if you're not flattening mobs like a steam roller, they're respawning and linking constantly.
Honestly curious if they actually playtested some of this content. Hopefully we'll get a patch soon enough that increases respawn timers or at least makes them dynamic, decreasing as mobs are killed faster, increasing as they're killed slower, etc.