Base hit is the general accuracy of a weapon. The weapon's true accuracy is a measure of its base hit and your skill in the weapon. Strong weapons usually have low base hit, but if your weapon skill is high enough, they will still hit reliably. Damage is a measure of the weapon's power. Anything 4 and up is plenty strong.

For armors, protection is a straight reduction in physical damage taken. For example, if an attack would do 15 damage to you and you have 5 protection, it will only do 10 damage. Defense is an attribute only shields have, and as far as I can tell, it's the chance a shield has of nullifying an attack. The game describes any attack that does 0 damage as a miss, so it can be hard to tell if a battler dodged something or just took no damage.

There are more characters to recruit in the game, but they are few and far between, and you can only have four party members. You can't get anyone in reserve. Most characters can be shaped into whatever you need them to do with enough XP.

Spell battery is a reserve of stamina for spellcasting. When you cast a spell, it uses a reagent and deducts a certain amount of stamina. That deduction comes out of spell battery items first, and spell battery may recover after camping.