Steve, you will not have much luck with the "First Bites" food. Did you also read my second article specifically on micro-foods? They really need something that MOVES. The easiest option would be live blackworms chopped into tiny pieces (they continue to live and wiggle, even chopped). OR newly-hatched brine shrimp (see Micro-foods article). I can help you find sources for either of these, if you need help.
Leaving them in the tank is fine, well, sort-of. The advantage of leaving them there is that there are probably a lot of micro-organisms already growing in the gravel, and they will eat these. And you can start adding live blackworms, which stay in the gravel, and the larvae will eat these as they grow bigger.
However, you may be frustrated by not seeing the larvae very well (they will be down in the gravel). The other problem is that if you are putting a lot of food in there (such as brine shrimp), it will get in the gravel and rot. And you can't clean it out without sucking out the larvae too. Is there any way you could remove most of the gravel before they hatch? Is your filter intake small enough that it won't suck them up?
If you want to remove the eggs, just remove the whole plant(s) that they are attached to. Or do it as John suggests.