Goats milk is probably one of the better substitutes but there is a good recipe which I guess you may have found... google "Leerburg milk replacement".
Definitely do not flea those pups... the chemicals in those flea products are much too strong. Best you can do is keep pulling off the fleas and perhaps bring them inside your home once the fleas are gone to prevent the vicious cycle...

I waited until 3 weeks and used a tablet to worm my pups... doing it every two weeks after that. I then supplied the new owners with the 9 week worm treatment and advised them to begin worming with regular puppy wormer after that.

Have you looked into weaning them? pups can usually wean at around 3-4 weeks... there are lots of different things you can try. I usually start with a sloppy mixture of fatty beef mince mixed with wombaroo/divetalect or whatever milk substitute you've been using, however last time I started them on straight beef mince, in little balls... just roll a little ball and offer it to pup. let them sniff it and they may or may not lick at it. contrary to popular belief, weetbix and milk is NOT a good starter for weaning puppies...