Bandage, tape (is more needed in later areas of the game), Wish and Meat are 100% self-explanatory.
I carry ghost as my assigned buff because it's not a top priority buff. When we all die and rez I'm too busy healing/catting to have the time for a high priority buff, plus I'll need my rage to heal rr4 heals. If I carried Defib I would carry rock instead to be able to rock them as soon as I've defib'd them.
Diagnose - how well you survive really difficult situations will determine how far you get in the end. Diagnose is in general a pretty bad healing ring because of how much stamina it uses, but you WILL need the extra heals when Wish, Bandage and possibly your supercharger are on re-use. You WILL need this, make no mistake of it. For Bloodlust Diagnose is invaluable at keeping aggro and for Bats it helps me to build rage.
Loltegrity/Fitness - The crew needs 11 buffs only so one person can go without carrying 2 and it makes most sense for that person to be the healer. Carrying attacks in those 2 left-over slots sounds like it'd be a good idea, but it won't really work: it'll use WAY too much stamina. As healer I usually have aggro so I can't go rest while we're in combat. I also need my stamina the most when we're in a pickle so that itty bit of stamia regen loltegrity and fitness gives can be essential. The willpower boost is also really neat.