That mix IS a little on the strong side. I don't know about others, but I like a pretty sterile mix to put newly-rooted clones in. ProMix with extra perlite would be an example. I really think you just ended uyp with too wet medium and those BUGS! Where are THEY coming from? Fungus gnats would have a larval stage indeed but I've never seen it. They love rich organic sloppy muck though, that's for damn sure!

Crap. Seriously go grab yourself a sack of promix or something because it just SUCKS to get roots- that's the hardest part- and lose the clones due to some annoying bullshit reason like a transplanting mistake!! Oh man I feel for ya.