Hello Lozaa, I will do my best to answer your questions. 1st off I would note that the clones in the pictures are very dry. I would not let the plugs get completely dry like that for more than an hour or so. Because they are well rooted already, they should be quite strong so you're probably good. That is the wilting. I agree with the other person, 10 ladies is quite a bit for a 4x4. You would have to basically trim and train them to be single cola plants more or less. Why not just easily grow 4 plants in a 4x4 and do a lot less training.
I primarily run hydroponics, but my experience with coco is that it is somewhere in between soil and hydro.
PH kind of reflects that. 5.7-6.3 PH It is a very airy mix that requires frequent watering because it dries back faster than soil. That's good, but also more work.
your clones are well ready for nutrients. Don't get crazy though, start with like 1/5 concentration of whatever you normally top out at. clones need very little nutrients. They are barely able to photosynthesize yet. Same with the light. Start low and work up, don't blast them immediately with 800watts. They can't use it yet.
A drip irrigation system would be awesome because of the frequent waterings required for coco. Look around at other coco grows to get a feel for the timing on when to water. It may be something to try for your next grow though, those clones need to get transplanted soon. A simple irrigation system would include a bucket, pump, about 6 feet of 1/4 tubing, a few 1/4" fittings and a timer, that's it. drip irrigation systems may clog because of nutrient salts building up and drying out in the tubing. Run shorter and quicker drip cycles to keep the lines wet and not overwater your girls.
don't hesitate to ask any further questions, I love to offer my terrible advice at will. ๐