Thanks for the explanation. It's great to hear that it will be possible to grind without restrictions near the end of the game.
Usually, I would hoard 99 potions and never use them, but being stranded on an isolated island, it's probably for the best to adapt myself to new conditions. ;)
Yeah, I noticed that most areas change in some ways at some point (including new enemy spawns), so I've been revisiting all maps regularly so far. The fight against the rampant crab was a close call, so I will continue to kill everything in sight, hoping that the game will actually be "very easy" at some point. :D
Ayami's solo segment after the shipwreck is actually rather tough when fighting all enemies (which made me use up every single Potion that I had found), but that was on me, since I was too "afraid" to interact with the healing spring and saved that for last after killing all monsters (after a few decades of playing JRPGs, wisdom can turn into stupidity). I simply didn't expect to receive free healing, and now that I know about it, I'd rather backtrack regularly instead of "wasting" healing items. Anyway, now that I have a full party, I won't complain if the game gets easier. :)