Well, given that salamanders can be recruited before landing in the volcano, I don't think it's that weird. You could think of it as stopping by the salamander village to pick up supplies before dropping into the depths.
It's been about 6 months? I think, since I beat the optional final-final boss, so I'm not even sure how long it's been since I smoked the one I think you're talking about. I think I'll compile all the notes from here and format them and send them to Baas, later, so people can reference everything quickly if they come this way.
For the legendary weapons, I suspect that that's kind of one of those things that the developer assumed that the community would pool together and discover and share around the recipes. I'm not saying it was a good thing or not to do, but I feel like given the large number of items in the game, and the obscurity of many of the hints, that was the plan. I didn't actually expect there to be a wiki for this game because it's so unknown, but there is, probably exactly because of that.
I still have not been able to go through and see where certain parts of the translation are messed up, even if it doesn't look like they are. It's pretty perfect in most parts, but some are questionable. There's several bits of as-far-as-I-know-player-visible untranslated dialogue, but I think it's in a place very few people will land? Or the dialogues themselves require hyper specific triggers? So if we assume that, maybe some hints were lost in the final push to release this.
I never made any legendaries, myself since even though I could see the recipes while translating, it didn't feel right to use them. It's totally reasonable that would bother you, though. The optional final-final boss can respawn though, I think, if that's any help, and more firepower during those battles is always good. At the same time, it's probably a lore thing on top of the fact that they are hopefully nice weapons.
Lastly, what do you mean? If an item has a skill to teach, it should say. Could you give me the name of one of the items in question?