Phew, Thats alot of thinking.
Content=this is what your aiming for are you looking to do tough content or level up or maybe grand gaia or arena perhaps raid class battles or maybe you just want to breeze through all content finding out what you might want to do helps build said formula below
Mitigator=someone or something that adds a percentage of reduce damage it looks like this 50 reduction of damage for three turns.
Support=something or someone that adds a benefit to the whole squad these things come in forms of od gauge or buffs there purpose is to add the buffs you simply lack.
Nuker=these units are a favorite of many there job and only job is to do damage there damage should be higher than all non nuker damage a support should not have higher damage than a nuke
Hybrid: these units are rare but they exist these units are the support/nuker mitigator/nuker we have reached a point in brave frontier were some units = 2 units these end up being universal units or staple.
Fun fact: the first ever staple unit release was arumat 2018