Oh right. Well, strictly speaking yes, you can equip underwear as a helmet. But you must also equip Socks as a shield, Gloves as an Accessory and so on. Essentially, you lose half of your equipment slots - and that gimps you, because that's potentially a lot of stats (although not so much in the demo).
Anyhow, I think I've figured out the problem. I need more features in my translator to fix it, but it is doable.
Also, quite handily, you're wrong on text-images. When I said that the programmer had some serious skills, I meant it. The only text in the demo which is not an editable string in the game somewhere is the help screens you get when pressing F8. Everything else is somewhere in the code. The text you mentioned is scattered across a few of the Ruby scripts.
Incidentally, whilst I didn't try it out myself, someone did mention that you can glitch your way through the fight, by expoiting the fact that the spear/pole-axe type weapon can stab through doors, and bandits can't seem to open doors. However, as you'd expect, the fight is supposed to be unwinnable, so nothing happens even if you do beat them all.
Finally, Minnie's accuracy isn't that bad, I think. The issue is the D&D style rules, where armor causes attacks to miss rather than reducing damage. At least, I think that's what's happening in the code...