If the fur doesn't grow back by the time they start scooting around talk to a vet.
I wouldn't be to concerned about it as some rabbits are born with very little hair, just make sure they are warm enough and eating well.
I'm not expert but my rabbit had two litters.... ya they got out of the cage the first time and the second my little brother took them out. But anyway my rabbits only needed one time to get a good litter.
Let him get some alone time for a bit try not to bug him too much for a couple of days. Let him settle in and every now and then check on him so he can get used to you. Rabbit can be quite jumpy so take it slow.