As far as the rewards thing, I've noticed most fairies will start rewarding again after you pass the point your pet was at pre-crash. So if your pet was at 500 Gfs pre-crash, and you fed 1000 gfs to it, you should get all the rewards for after 500 gfs. Not sure if this helps or not, but it's what I've noticed as I've re-fed/re-added collection items/etc.