There are some companions i've noticed lately that are just a pain when it comes to battles that used to be my best companions!
these include:
Dead mike
Old scratch
Ponce de costa
Don fidelo jimenez
Nurse quinn
Mean bill tew
Ethan miller
And growlin' ringo

as you can see a lot more than 3 (talking about benching)
So i think that you should be able to like set off companions in your house/in a tavern (only like up to 6-8) in that range because sometimes ill get the worst hands at the end of a dungeon and die..
Like when i fought one of the last dungeons in marleybone (beachbeard) and i got ponce de costa and one other (didnt let me choose my companions for some odd reason) so i lost and had to do the whole dungeon over again for some reason and that wasted uhmmm...1:25 minutes of my day so idk
if anyone has tips i know old scratch isnt as bad with his upgrades which i am doing right now but for all the others please help :P
Sneaky wolf parker level 54 soon to be 65 swashbuckler arrghh