Indoor tree start problems...

I started a PILE of trees indoors this over this last winter. Everything was going great until I started fertilizing them with some high nitrogen bat guano fertilizer that I inherited from a friend. They've been on a steady decline since.

I applied the guano as a fresh brewed tea twice over the span of two weeks.

Once I started seeing adverse affects, I flushed everything thoroughly with tap water and pruned back any bad looking areas.

It's been about two weeks now and they seem to still be on the decline.

You can view photos of the blackberry, pagoda and persimmons here:
https://www.dropbox.com/sc/grvz1aipu7p6fxh/7ENY2ecG4u

Any experts in here that can help? Thanks!

The one picture almost looks like spider mites. If you look very closely do you see any sort of webbing on the undersides of the leaves?

Thanks for looking! I don't see any signs of spider mites. We do have a HUGE fungus gnat problem that we are treating with azamax. Can they cause this kind of problem?

find the highest quality compost or wormcastings you can find. add some to the top soil about a 1/4 inch. and water in, do this when they need watering, part of the problem seems to me that your watering too much( aka fungus gnats)

start giving them daylight outdoors little by little if possible, you want them in the sun soon without shocking them.

I think that does look like too much water and too much nitrogen....I would probably try repotting a few and check on the roots. Maybe a better drained potting mix also...I add a lot of sharp sand to my homemade mix. I am pretty sure most young tree starts don't need much nutrition until they are planted out. The leaves look familiar enough I am sure this is something i've had happen in the past

Thanks for all of your answers! I'm REALLY pleased to hear it's not a hopeless situation. I'm pretty attached to these little guys!

I definitely got overzealous when I inherited a friends' grow room gear...

Once again, LESS seems to be MORE!