Both the fur babies are a bit young in my opinion. Id think by the time the pups can grow to be more mature closer to a year and be fully potty trained it would be better.
I have a fear that the pups might get rolled on, or pushed off the bed, OUCH!!
Also, with not being fully potty trained the kids are not old enough to take the pups to their potty spots if need be, etc.
Give it time....I think it will be worth the wait.