I wouldn’t recommend this Grow Bro, this could affect the PH of 5.8-6.2 for the coco. The soil that seedling is in looks very wet and dense and could dampen off the tiny main stem. Seedlings require very little water and a lot of humidity. I would mist and place a clear dome over that plant and give a shot glass or 2 of water every 2-3 days after this soil dries
Coco needs to be fed a balanced NPK with a proper pH/ppm daily. Your compost most likely won’t break down the nutrients quick to feed the coco having to water frequently. Also as mentioned, mixing different soil types can have major hiccups. Different absorption rates, pH requirements, and other factors play a great part in your plants uptake.