i personally hate hermits. Everybody said they'd be fine, especially the scarlet reef hermits. They all suggested i put a bunch of extra shells in there so they wouldnt fight eachother for them and mainly so they wouldnt kill my snails for them...so i did, but no matter...they've still killed about 15 of my cerith snails and i'm finally down to only 2 hermits left in the tank...all the rest have been found and pulled out. But i tried 4 or 5 different hermit verieties, and all of them were wearing cerith snail shells in the end
imo, i'd go with snails instead...they're much better cleaners anyways. I'd get about 35-35 cerith snails (the best imo), about 10-15 nassarius (they'll stay under the sand so dont worry if you dont see them) and about 20 or so astreas...well i like to get lots of snails as long as they've got enough food to eat. Many people will say "only 1 snail per gallon" because they need enough food to go around. I've got plenty of food in my tank for them so i go kinda overboard on them...i got about 70 or 80 snails in my 55. imo this is no problem because go out in the ocean...they're all gonna be crouded in one spot so crouding them is no issue, and i've got plenty of food, so they're not gonna starve.
Shrimp...if you want a peppermint shrimp, you can get one and they're good for aptasia (pest anemone) but you're not ever gonna see it hardly..they only come out at night for the most part. The blood reds come out more i think, but i'm thinkin i've seen that they can be kinda aggressive towards other stuff...not sure tho. Cleaner shrimp would be the way to go tho imo. They're really active, clean the fish, and will also clean your hand when you put it in the tank lol.
But many people mix shrimp, but i do think you gotta be carefull about it, i just dont know what goes whith what for them.
One more thing...you've got a 72 gallon tank, but you're only getting a half gallon a day (yes only...i get almost 2 a day on my 55). You dont happen to have any glass tops on your tank do you? If so, do you have a sump?