All potential bonuses

I've been racking my brain trying to think, is android bottomwear the ONLY option we have for HB then? Since the stirge set is rather outdated and lost at sea?

If you wanted HB, you could make lvl 26 common pants with it, then wear an overall on top and the skill stays in the skillbook, I'm pretty sure it's a glitch but still.
About the "level" requirement for the skills, it's char level right? because a friend got SE on lvl 80 gloves.