Thank you for rescuing your wee grease kit. If not for you, it wouldn’t have survived. I understand your concerns Kay. However, the kit is getting milk and not solid food.
I’m not sure how you’re stimulating but triangle method here is successful for most foster moms. If the kit doesn’t poop by tomorrow, call the vet.
https://www.youtube.com/watch?v=enJrSU-nqCc
Here, too, is general info we give to new foster moms. Maybe you’ll find something to help you out. Kittens cannot regulate their body temperature so they must be kept warm. Kittens cannot digest food if they’re cold. If you haven’t already, make a nest for them. I think the best way is to place a heating pad, on LOW, covered by a towel and a soft blanket. Also, put a soft shirt of yours in their nest so the know your smell. Be sure to provide a “cool” spot for the kittens to crawl if they get too warm. Keep the kittens together so they can snuggle.
Here in TDKland, we recommend Goats’ milk for kittens. Cats are lactose intolerant and can’t digest cows milk. Goats’ milk is full of nutrients, probiotics and gentler on their tummies. This can also regulate their poop. If you are using the Goats’ milk concentrate, mix it with pedialyte. Pedialyte gives an extra the extra boost. Keep in mind if they seem lethargic put a dab of Karo syrup or honey in their mouth. Sometimes this is all they need to give them the added energy boost to get them eating. A smidgen of mineral oil in their formula can usually help them poop. Here are some links with good information on caring for your wee kits.
http://messybeast.com/handrear.htm
Good Luck and do keep in touch. I want to know how your kit is getting along.
PG