Sounds like you're doing most things right, but a couple of things to think about:
Stay clear of the home-made foods, a commercial kitten milk replacer is much more consistent in its protein content etc. than something you'd make yourself.
Kittens have real trouble maintaining their body temperature, so you need to keep them warm with external heat (keep the room warm etc). Obviously don't overdo it!
I'd be making real efforts to find their mother and reunite them if you can. Depending how long you've had them that may or may not be possible (she might not take to them again), but kittens learn loads of stuff from their mothers (e.g. how to groom, how to use a litter tray) so if they can stay with her until they're 6-8 weeks old it'd be best. Have you asked all your neighbours about them?
There is loads of info on the web I'd imagine, but I'd advise you call your local vet for advice if you're worried about anything. There's a lot of rubbish on t'internet.
Al the vet