Lol... Okay, don't worry about it they are fine. However next time water them right as you plant them of right before and saturate the coco. Now funny thing with coco, I have found that you want the medium to get a little in the dry side for the first two weeks before watering because the plants otherwise seem to get lazy and won't grow. Once they get to a decent size for the pot. Or can dry out the medium over night then switch to watering 2 to 3 or even 4 times with about 20% runoff to keep whatever the plant isn't using from building up in the medium.
BTW good choice with coco for hydro. The coco acts like a buffer to protect from wide swings in PH and you don't need to worry about a pump blowing or long power outage killing them like you would with dwc or some of the others..
Watch you Ph, canna Is a good line, little pricey but good none the less. Don't waste your time with the booster, I wasted plenty on that and it did nothing. I wanted it to do something but it was the same with or without. Since this is your first time I will suggest you just use the A+B and maybe just use a little rhizoctonic and cannazyme which will protect your roots from disease and the tonic works very well. Don't go adding other additives from other brands until you get a few grows under your belt so you will at least get a feel for what to look for. And don't freak out and do anything rash, 9 times out of 10 people do more harm than good when they do that.
With coco, you are growing hydro, so yeah once they are established you want to treat them like hydro and don't let the medium get dry!!! So the fun part is figuring out how to water so many times or automating. I program micro processors so I made a little setup that monitors soil humidity and waters at the set amount of moister in soil, which is set at 50% max water holding capacity of the coco medium and the plants love it. I used to use blumats which was a very analog way to do things but they either gave too much or too little. There are some interesting setups I saw on this site and others to automate and I would suggest taking a look because once those girls get big it's almost impossible to water them as much as they would like without being there to water at least three times a day. You can get away with twice, but three is better.
Good luck, don't worry as long as they are alive they will grow. It's a WEED after all and you would be suprised at what they can handle. When in flower an oops can cost you some overall weight in the end but not during veg.
You watered till runoff, now let the top of the medium get a little dry before you water again. Depending on your humidity and other conditions that could take 4 days a week or even two. Then you will start to see them start to dry up quicker so you will want to gradually increase frequency and start to not let the top ever get dry again. That's when you treat cox like hydro.
As for the light, it doesn't matter just raise it a little if you get bleaching on the leaves.