The smaller clutch of eggs disappeared overnight, and even more strangely, so did a new spawn of BN eggs in another tank. No clue what happened, but no doubts they'll keep spawning. There are gravid females in both tanks, it's just a matter of time. If it happens again I'll try moving them to different tanks sooner, but it may have just been too much disturbance for young/inexperienced males.
I've been feeding the fry microworms and finely ground HBH 8 veggie flake. I have brine shrimp eggs, but they don't seem to be necessary. I've read that the first month is the most critical, they're halfway through that now.