Will they drink the KMR if you put it in a shallow dish for them? At 4-5 weeks, they should be able to eat wet food on their own and shouldn't need bottle feeding.
But if they won't eat, or they won't slurp up KMR, I'd give the bottle a go. The bottles they provide at our vet don't have a hole in them, so make sure you make one if it doesn't have one. Room temp should be fine. It can be kind of messy, so clean them up with warm water on a paper towel.
Here's an informative site: http://www.kitten-rescue.com/feeding_techniques.html
Of course, the bottle feeding info is for just born kittens - 2/3 weeks old, because they get weaned after that.
...but I wouldn't think it'd take too long for them to start eating the wet on their own at this stage. Just keep at it.
Just make sure you've got a warm place for them to snuggle in - warmth is important.
They should also be taught to use a litter box - make sure you get clay litter for them, clumping litter is dangerous if they get it in their mouths (it clumps if they swallow it!)
Again, I'd check out the kitten rescue site.
What a wonderful thing you're doing.