I don't like the "probable imminent death" path. I prefer the "probably friends" path. I'm all for testing Muma, but let's do it with something that doesn't result in death if we guess wrong, so let's trust Muma for now and go left.
The destination is Alide which would be nice. We should start thinking about what to get, assuming it's the same choices as before. Ask Cherchiel what type of weapon she prefers and how much that would improve her combat ability. Though Muma considers her a somewhat useless companion, so maybe I'm mistaken in assuming Cherchiel is a brawler type, or she is but without divine strength to make it work.
I propose you arm-wrestle her to test her strength. Or just ask her outright how she'd do in a fight against, say, a priest from the previous floor. If she is indeed not useful in a fight we should adapt the combat strategy to give her more of a support role. We can compensate for her lack of muscles by giving her items such as poison gas grenades. Also consider giving her your antidotes. You don't really need them since you have magic, so enabling Cherchiel to heal you is more useful.
If her strength is completely lacking we should consider leaving her behind in a safe area. Despite what Muma says Cherchiel is definitely useful as moral support at least, so we should not put her in risk she cannot handle. Also she can watch your supplies. You're carrying an awful lot of stuff around, enough that it makes you noticeably slower, so consider giving Cherchiel all but one of your rations and water supply.
You still have a Boar Mask. I forgot what it does, if anything, so consider trading it away when you reach Alide. An extra spell will probably be more useful. We desperately need offense. Picking an offensive spell seems reasonable, but chances are we'll just get something like Fireball which effectively does similar damage as Icicle and doesn't make you much stronger. You're a support mage, so getting a support spell like Weaken, Chain or Slow would probably have more impact on your survivability.
Once you do find Alide consider delaying getting something and facing a danger first. You get a free heal from Alide, so better take that after you got hurt than wasting it.