I think I'm pretty safe in saying that this is the final, climactic, battle for this book. Whether it stays in one place geographically, though, who knows? But any steps it takes would have to escalate it... so I could see the protagonists going to Hel's lair, for example, but probably not returning to the Godsmoot for any length of time.

I could be wrong, of course! Now that I've said that I can think of ways the Godsmoot could be an escalation. What if Hel decides to manifest there? But it would still have to be part of this same battle. No travel time or adventures on the way, etc.

As far as checking in with other groups, sure, but that would be saved for the denouement. Seeing them in this sequence would kill the momentum unless they were to have an immediate impact on the fight. Which is not impossible, of course! Also one-panel cutaway jokes, etc. But it would have to be something fast and unexpected; there'd be no set-up or establishing strips.

In the denouement, though, anything goes, I think. Check in with whomever we want for a couple strips at least. It's not what usually happens but I can't think of any narrative reason it couldn't. Team Evil, sure. Azurites, why not. In Good Deeds Go Unpunished, Rich says that
Spoiler: which is indeed a spoiler
"I love writing the Katos, but...their part in the overarching plot...is mostly in the past. Hinjo, on the other hand, still has a major role to play in events yet to come"
so there's that coming up, for sure, and I wouldn't be surprised if we get some setup for it while tying up the other loose ends. Then again, I wouldn't be surprised if we didn't! It's wide open.