. My first runs seedlings just took forever too. Put em in compost and burned from babies. Seems like you've got it sorted to a good point now though, those plants in cups a few pages back looked great honestly.
I know you were talking about your setup and exhaust and humidifiers etc. too..I wouldn't even worry about them being in your setup yet, until you get em into there next pot size and hot lights on em. Use this time to dial in your space(turn lights on high, see where temps land, get a fan speed controller and see if you can get it low enough to keep moisture in, etc)
I think those little ladies can hang out with a little fan on them and be quite happy for a week or so. Now that you have
promix and they're growing you'll be surprised how fast they go after the next transplant. Gotta have that space ready for them so you're not "doing it live"so to say.