I probably didn't explain properly, I was looking for a mastodon account to follow that posts on mastodon only when a new thread is started on the website here. Looks like @TrekSite@tenforward.social is what I'm looking for, as the @startrek@startrek.website one posts on mastodon every single time a reply is made on the website.

Thankyou for that input, you've explained the gaps I was struggling with.

The big mistake I made was taking "to protect their civilian passengers" to mean some other civilians we didn't see, when in fact it meant the remaining two castaways (Buckley and Oriana). I didn't give enough weight to the facts that the area is prone to sporadic heavy snow storms, and that there was no time for a thorough initial search by the Enterprise away team. It is possible the Peregrine crew deliberatly launched their plan just before a big storm was incoming, to make sure the Gorn would be trapped in it, which of course makes sense that the crew themselves would all die from Gorn attacks or from the storm (as supported by M'Benga's assessment of the bodies outside).

I'm still a bit hung up on the plasma grenade not killing the gestating Gorn, but I suppose it is reasonable. I think the Peregrine captain's log even mentions "but he didn't succeed" (in killing the Gorn inside himself) or something. If gestating Gorn can survive later stages without being "attached" to a living host, this may also give some clues into possible twists with the Batel situation.

I will rewatch with all of this in mind. Thankyou for untangling my brain-knot!

I suppose "Gorn just die very quickly in the cold" is the simplest explanation, but still leaves a lot open.

I'd love for Hemmer to return, but feel like the sheer height of the fall makes it quite conclusive that he'd die. Maybe I'll "warm" to the idea (see what I did there?) if the writers can make it work reasonably. It would be particularly fitting if Hemmer's unique physiology was the thing that means he can survive, as his preference for the cold is the opposite of the Gorn, and he even says "Just like Andoria!" before he jumps jumps off. Maybe if Batel is able to be saved from her Gorn infection, the new medical knowledge could be used to save Hemmer if he is indeed semi-frozen/hibernating or something. It could make for some interesting further development of the Aenar race also.

The possibility of revisiting the specifics of this episode could be why they've left these loose ends that I'm questioning in the OP.

Re-watching SNW.