"Bean" & "Bitey"?That's freaking adorable!
As you figured, they were hungry and scared! Poor things...if they're warm enough & seem interested
you can feed them fuzzies every 5 days (but no sooner than that), that should be OK. Don't you love "dumb" pet stores & "enabling" friends?
I wouldn't expect them to "grow a little" on fuzzies...that will be "maintenance", while they settle in, btw. I hope you can educate this shop in the future...but if not,
encourage them to NOT sell snakes that they don't understand & aren't doing right by...otherwise, you're going to need a bigger place.
I'll bet these progress rapidly with your good care...but glad you're quarantining too. Hopefully they're healthy.