Callistemon21
Have you got sun loungers padded garden seats ? You could use the long cushions from those with sleeping bags.
I was about to suggest this! Some years ago when my son and his FF at the time unexpectedly wanted to stay a night when we already had a houseful (family from Australia, local family, too), I improvised using lounger cuahions for two children aged 12 and 8 which worked very well.