Seems a little unbelievable to argue that the people who set up a settlement outside the dungeon won't be found inside it. The upside of bringing Gisena is that we never have to talk to the people in there, Gisena can just talk to them for us making Tyrant almost impossible to proc! This was 90% of the reason people voted to bring Gisena with us in the first place.
The question is not whether they are inside. It's our likelihood of encountering them. For some reason, the fact that we could encounter people is being blown out of proportion, to the point that it's being treated as much more likely than it is. The Temple is fucking ginourmous (as I said before, it took Vers from evening until morning to cross from their encampment to the main entrance), and we know for sure that there's some definite combat risk in going in. It's not sensible to assume that we need to pick a less effective option for something we know will happen (combat) to hedge against something that's unlikely (social encounter). (In this scenario I'm imagining that adding boosted Gisena's combat ability to our own doesn't match the extremely high offensive potential of Panoply, which is debateable, but I think still easily true.)
Let's look at the possibilities:
1. No Encounter (most likely). Social irrelevant.
2. Adventurer encounter, but they aren't a threat.
2a. Adventurer's aren't demanding or threatening. Social doesn't matter.
2b. Adventurer's are demanding or threatening. Social doesn't matter, because we can just fight them and win.
3. Adventurer encounter, but they are a threat. Social matters.
3a. Adventurers aren't demanding or threatening. Social doesn't matter, because we can navigate neutral conversations just fine.
3b. Adventurers are demanding or threatening. Social doesn't matter, because if they're willing to insist on a arbitrary rule or threaten us they'll attack us and Gisena anyways for our loot.
Hedging against social encounters assumes that we meet people at all, that those people are effectively strong enough to pose a threat, that they're in a very specific band of degree of behavioral hostility, and lastly that Gisena is capable of both defusing people hostile enough and strong enough to be a threat to us, and defusing us right there next to her as we hear them being hostile. Somehow, I feel this is a lot of assumptions.