They’ll be fine there as long as they are dry and its not too drafty. Being able to cuddle up to each other for warmth and reassurance would be a good extra. You might like to give them each a litter pan with earth in it so they can start to housetrain themselves. Earth or potting mix might be easier for them to use rather than bought kitty litter - and the earth can go back into the garden once used. A cover/towel over part of each cage will help stop drafts.