no, definitely don't take them away from her! they need their mom even if she has no milk. take them away as briefly and rarely as possible. I think every 2-3 hrs should be fine. yes, she might get pissed off to the point she rejects them, but don't make that decision yourself. baby kittens need their moms as much as baby humans do. re: the puppy formula vs. kitten formula- I know there is one thing cats need specifically, which is taurine. not sure how much of it kittens need though.
my cat hated the bottle, we basically were squeezing it down his throat and force feeding him. he only latched on and suckled once. I know you don't have a ton of time on your hands, but if you could find some stuffed animal no one cares about, you could try cutting it, stuffing the bottle into it so only the nipple sticks out, and see if they like that better- more like a real cat.
just do the best you can, but like a pp said, even one kitten is a full time job, it's likely fostering them out is their best chance.
btw, I'm not doubting you, just wondering, how can you tell when a cat has no milk?