I haven't any suggestions re: the short time between flights other than those already suggested. BUT I did manage the sleeping bag problem with the carry-on. I bought a flannel sleeping bag which is quite small and rolled up into my backpack cum purse. That with my carry on were OK with Delta-Alitalia.

If you are small enough, the youth sized sleeping bag might work. Anyway, the flannel bag was fine, kept me warm and several of us were able to stuff it back into its container for the trip home. Good luck with your trip and ENJOY!

Jo in Sunnyvale, No. California