I agree with the others on this...try the canned pumpkin and take samples into your vet. I really can't see that the Petzlife can give the runs..but who knows.
Could be parasites but I would rather be safe than sorry. Maybe Mimi had something and passed it on to Moose? Never know. Keep us posted.
Give each of them a couple tablespoons of nonfat vanilla yogurt or the plain for breakfast and the pumpkin and see how they are.
I just switched Izzy to The Honest Kitchen (raw freeze dried) for dinner and the yogurt for breakfast and she is doing great.