Thanks!

The base inaccuracy of a weapon (in degrees), the higher the worse

Also what does error mean on ranged weopons.

Oh, thanks.

If I recall correctly that refers to their difficulty/level, for example lowest level/easiest boss to defeat (typically the closest to your beginning location) is numbered 1, and the most difficult 4

What do the numbers under the bosses.

Thanks i'll try that.

Miniboss castles are very good experience/looting opportunities but they can also easily wipe your team depending on the region theyre in, I'd recommend going to them as long as youre well prepared

Thanks the farthest i got was to the machine man, he killed all my dudes and he had like 50 health left. Also do you reccommend going to the mini boss castles or not.

It's been a while since I played but here's what I can remember:
Keep your team members well stocked with restoration items
Practice formations that keep your team together (and provide more visibility), but not too close as explosions can be very devastating
as far as skill points go, I'd split them between each members specialty and health (maybe a bit more focus on health for closer range specialties like melee or more specialty points for ranged), thats atleast what gave me pretty good survivability
Also throwers are very devastating (especially at higher levels), its good to have atleast one on your team.
But that's just what I've gathered from my experience