IMO, the one that is not feeding regulary is not "content" with its living arrangements..While your temps and all may be correct there is SOMETHING that isn't kosher with the animal, could be bedding,lighting,enclosure any number of things..Of which you'll have to figure out..Have a hide box?
How and what are ya feeding..Many brongs are very timid and eat dead left overnite..
On the nervous unacclimated one, Wish ya luck, At that age and level of scardiness I'd write them off as such, but would not Dare say it couldn't be fixed..But it would take one VERY passionate man or woman..