I completely understand how you feel. I found 2 celebes half beak and 2 swordtail fry in my 55 gal all in the same day...talk about a spazz attack. There are these really neat "net hatcheries" that you can hang on the inside of your tank, so they will be in cycled water with plenty of aeration from the rest of your tank with a stable temp. Mine was only 5-6 dollars I think. I lost one half beak and one swordtail since I found them, but the swordtail that has made it thus far does sometimes sit on the bottom of her net and then swim around for a bit, then sit some more.
What some others on the forum suggested for feeding is frozen baby
brine shrimp. I've also been feeding mine tetra-min crisps, tubifex worms, and bloodworms (all very finely ground up). You should be feeding them 2-3 times a day since they'll be growing so quickly. Best of luck to you, I understand how exciting and nerve racking it is!