My first take is that you are trying far too hard and the plant doesn't appreciate all that attention. Cannabis knows how to grow without help from humans. Think of these as weeds. More like crabgrass than some exotic hothouse rarity. Give them a good home, then stand back and keep your hands to yourself until they get a good start. Don't overfeed, don't overwater, avoid transplanting unless absolutely necessary since that always damages a few roots. Just stand back and keep your hands to yourself until it is 2-3 times this size. Your soil looks good, with plenty of perlite for drainage. Personally I use cactus mix for exactly this reason. A plant this small in soil with built-in nutrients should not need any additional feedings for quite a while. Looks ready for a deeper pot to provide better drainage and room for lots of roots, so go directly into something that holds 4-5 gallons rather than moving it two or three more times. Let the soil dry out before you water again (typically every 3rd day or so).
Follow the how-to forums, but mostly to identify and correct problems rather than being too proactive. This one looks like it still has lots of life in it, but in this picture it appears too yellow. Too much water? Fertilizer burn? Light bleaching? Get it stable and give it time to bulk up a bit, then decide if anything needs to be done to or for it.