Advice appreciated

I tried searching the forums because I'm sure my questions have been answered before, but I got super overwhelmed. Feel free to point me to the correct thread! Ok, so a couple of days ago we hatched our Carolina mantis nymphs. I have them in a 3-gallon enclosure, with the soil, plastic plant, and wood cave that came with it. The habitat said it was good for praying mantis. I added a square of tulle to the lid to help keep the nymphs and flightless fruit flies better contained after reading that advice online. I have been misting once a day. I added a small bowl with Flukers cricket quencher in it for their water source since it was the only bug gel I could find near me. I waited a day after they hatched and then fed them some flightless fruit flies. I read online some mixed stuff about how often to feed at this age, but I was going to just add a few more anytime I stopped noticing any still in there. I don't have their enclosure near any windows lights or vents. My house is usually between 72-74F. They seem to be doing well so far but this is only day 3. Is there anything I'm missing or doing wrong? I plan to release a bunch of them in the garden in 3-5 weeks which is when I read they need to be separated. I would like to end up keeping one as a pet. Any recommendations on this? I know I wont know the gender until full grown but we are ok with either gender I think. Any advice is appreciated. Our only previous experience with mantids is a previous hatch and release learning experience with Carolina mantis (indigenous to our area so they are safe to release). I've never kept any beyond a month.

Can I see the setup? I don't like soil or really any substrate when they are hatched, Food gets hid in there among other things. Feeding is ok and don't worry about them being older, if it is warm where you live they can go outside now, or better after the first molt. If it is getting cold out, they won't survive outside.

Sounds like a nice setup for going more natural route with substrate etc. I never have substrate in my enclosures, other then coco fiber in a few setups sometimes, because of the high risk of mold and pests.
An important note is that mantises will not eat gel water. Mantises drink water from misted water. So just mist them like you said you are doing and they will be fine.
As for feeding frequency I would say feed them once a day. That is what I do when they are this young. And then do a skip day once a week, say skip feeding Saturday etc.
Also it is a bit late for Carolina mantises to be hatching, normally they hatch in March - early June. So they have all summer and part of fall to grow and mature. So releasing the babies now they may not survive if temperatures start to drop for the fall season.