Coco requires nutrients from the start to establish it's CEC with the plant. CEC is important because it involves the electrical equilibrium of the roots and the media. When the media is too electrically negative (too many nitrates and phosphates) the plant responds by losing positive cations (potassium, magnesium, calcium) to create a balance between the two. Coco has a very unique microscopic structure that it developed to deal with high salt content sea water. This structure is what allows coco to create a nutrient buffer and remain aerated while still saturated. This is one reason why you don't want the coco to dry out completely.
Imagine you have two electrodes in salt water connected to a battery. The electrical current flows from one electrode to another because they are in solution. If you allow the solution to dry up you wind up with salts dried up on your electrodes and no conductivity because the water solution is no longer present. Apply this kind of common sense thinking to your root zone and media and you'll start to understand why it is important to keep the media at least somewhat moist.
I start my young plants off on about 1-2ml per gallon of Canna Coco A+B in conjunction with a rooting supplement like Rhizotonic and calcium and magnesium supplements. I run 1/2 strength on the calcium supplement and about 1/4 strength on the magnesium. Around week 3 or so is when I dial back the calcium and start running the magnesium supplement at full strength. I begin watering my plants with about 1-2 ounces of solution every other day for the first week. Young plants don't need much water, and most of the moisture is lost to evaporation really. When I notice the media getting drier early is when I increase the frequency of my waterings not the volume! Sometime during 14 to 21 days old is when I begin increasing the volume of my waterings so that I can do just one per day and keep the media moist. When the roots are set and several nodes are present (5-6) I will then begin to water to complete saturation, this is usually about 1L of solution per gallon of media to get a very small amount of run off but it can vary GREATLY depending on the size of the plant and the heat/humidity.
I think you could totally cut out the molasses. That stuff is good for a biological system, but you don't have biologicals in coco like you do in soil. I use a molasses-esque supplement in my quasi-organic coco setup beginning around week 6 of flowering, increasing to a very high level during the last week when I've cut out nutrients.
I've had my troubles as well but I have stuck with the coco through it all. I compare soil and coco to skiing and snowboarding. It's easier to stand up on ski's make the "wedge" and weave your way down the mountain. The learning curve is gradual with a subtle increase in skill with every day. Snowboarding is hit or miss, you're either a natural or you spend all day on your ass. The learning curve is in steps, with stagnant skills that improve in jumps with sudden insights. Both methods will get you to the bottom of the hill. It really doesn't matter which you choose, it is just a personal preference, but after 14 years of snowboarding and 9 years of skiing I can surely say that I can make it to the bottom faster and in more style on a snowboard. Just like how I can grow larger plants in coco in the same time frame versus soil.
I've never seen young plants burned up like that. It has to be grower error on your behalf (not being mean, just stating the facts) and I think the next time around could go a lot better. Just make sure you have clean high quality coco, a good coco nutrient system, and if you're going to do anything resembling biologicals and organics steer clean of Botanicare Cal-Mag Plus. It contains EDTA as a chelating agent which will destroy anything beneficial in your media. I see many grows that just tank during flowering with this stuff for really no good reason leaving growers scratching their heads and tossing out suggestions from nutrient burn, to pH imbalances, to cal-mag deficiencies. Your mistake may have been as simple as failing to fully flush and wash the salts from poor quality coco peat so just stick to the fundamentals and I think the next time around will be fine
If you get a cal-mag supplement for coco I suggest Organicare Calplex (calcium), Huvega (magnesium plus micro), and Humega (humic nutrient chelation for uptake), with Seaplex (extracts to keep the internode distances short) or Humboldt Nutrients' Sea Cal (calcium plus micro with extracts) and Sea Mag (magnesium plus micro with extracts) with FlavorFul (fulvic nutrient chelation for uptake).