I also suspect a combination of things--left in paper towels too long, too wet, damping off, and burning up from fertilizer. I never use the paper towel method for new seeds. Every time you handle a seed, you risk passing pathogens to the seedling and/or damaging the tap root. Fresh seeds (but not too fresh--they need several weeks to set after harvesting before planting) really do not need to be soaked.
I personally have had terrible luck with Jiffy pellets--they are quite acidic and they tend to keep the medium too wet, IME. If you are growing in soil, I would start in a seed starting soil with absolutely no added nutrients or moisture crystal things. Anything that says anything like "Feeds for 3 months" is not good. Water very lightly, but do not let the medium get dried out. There is no harm in putting something over the top of the pot like a piece of plastic until the seedling breaks ground to help keep the moisture in. But as soon as the seedling breaks ground you need to remove the plastic.
If you are using an actual 200W light and not equivalent wattage, it is too much light for small seedlings. They will do fine for a bit under a small CFL light. A smaller light kept closer will be better than a larger light kept further away.
You don't want to keep your seedlings too wet or you can develop a condition called damping off where the stem rots right at the soil line and the seedling keels over and dies. I generally water gently around the perimeter of the stem letting the water wich up to the stem area gently.
If these are simply bagseed from a plant selfing and not the result of seeds made the old fashioned way with a male and female getting together, then you will have to keep a very close eye out for hermies.