Welcome to the forums 8)
I have around 50 young BNs (Bristle Noses) around 20mm long right now. When I first noticed eggs I removed all the fish in the tank except the father, mother and another young BN. Feeding zucchini, courgette and/or cucumber is good, as are algae wafers.
If I was in your situation, I'd remove the platy, feed daily and do partial water chnages daily. I've found that feeding rotten cucumber or leaving it in too long tends to make the water cloudy but it's not harmful. Try and feed just enough that they can all consume in 12-24hrs max.
Good luck!