Updates will be a little slow this week and next. Finally some color is coming back. I started a new nute line not that long ago and I have started giving the plant more water or more frequent waterings and it seems to be responding well
I see this picture she looks so sad man she is hungry! I think your problem is the way you water your coco because it looks dry from here. Coco needs to stay moist all time and plant should be watered at least once a day till you get about 20% run off, witch you should discard. (Drain to Waste). Some re-use it, I tried, you can up to a certain point (I will explain why if you want) but it is better to give fresh all the time. If coco dries out the pH gets fucked up and you have to start again (flush with pH'ed nutrient solution until run off is about the same as what you put in). If you change your watering practices you will see an upgrade on all your current grow.
I see you are worry about transplant I am guarantee you 100% she is perfect in this container for now and as long as you can keep up with watering. In coco you can grow a tree in a 5gal pot as long as you can keep up watering. In a bigger pot like a 5 gal it would be hard to water properly: no dry spot in the medium and enough air flow in the root zone. Smart pots are ideal for coco.
If I was you I would try to save her for learning purpose but at week 8 a plant in this state will take some time and TLC to bounce back and gain back it's vigour. When you'll repot I suggest to forget about vermiculite, and use fabric made container.
Growing in coco can easily gets pretty expensive: last run in coco I did I ran Canna full line from start to finish with the Cannaboost 120$ bottle FML it costs me over 400$ of nutrients!!! It was my last run in coco! Now a bag of 10k of dry amendments for soil costs 80$ and I have for years to come!!
Best of luck mate