Young brine is fine for the youngsters. In adittion, feed them a mix of ground Spirulina flakes and granulate (grind to dust!), or simply food for young fish readily available from your LFS. Not sure what is available where you live, but products like BabyMin from Tetra or Liquifry are often used. The youngsters are quite soon capable of handling Cyclops nauplius. Even if you don't feed them, several of them will grow up anyway - in a matured tank.
It's quite normal that young females mess up their first couple of nests - at least in an aquarium. But practice makes perfect. Believe me, at some point you'll be glad NOT to have fry
Good luck with raising the young uns