WPC,
Shame the hive was that bad but you have given them a good chance of survival. Just aim to keep them warm and they will do their best to survive. Better than being toasted in a controlled burn-off. Maybe you should get that comb radio-carbon dated!; might be stone age!
On a more serious level - were you able to recover complete frames of stores (and brood?). It is always a bear to sort out natural and wild comb, but it sure is very satisfying, when it all works out OK. Filling any spare space in the new hive will reduce Finman's 'vain space' and help them to keep snug, warm and dry if the main ventilation is at the bottom.
One year, with a weak colony, I found that covering the boxes in a not-so-good WBC with lots of layers of old towels over the fondant block was a good idea. I saw and could feel the towelling had sagged when the block was nearly all gone, so knew they were still alive in there without having to check too deeply.... Indeed the block was nearly used up - they had seemed to prefer the fondant to the other stores in the frames, which was probably a bit distant for a small cluster to find.
I would prefer to lay the block on a cover board (with feed holes) so it does not steadily run down between the frames, or at least on a plastic sheet for the same reason. Maybe you have thought about this already.
Regards, RAB