1st grow not going well, what should I do different next time

Hi there, thank you for taking a look, I beg of you to be patient because I'm about to explain everything, hopefully you can help me figure out what I am doing wrong so I can have a smoother 2nd grow. 1st I'll describe my setup and mistakes I think I made, then I'll propose what the potential problems could be.
This is my very first grow and I am sure the growth has been stunted from 1 or more reasons. I will attach pictures as well.
Strain: 4 seeds, Ambrosia "Jordan of islands" or whatever, (bought in Canada/given to me, not my first choice but they were free )
Light: Germinated w/ paper towel, 75w Fluoro for first 2 weeks. (2.5-3" tall, good looking leaves). Changed over to new 400w HPS w/ a built in ballast. Put the height at 18" overnight w/ out a fan (big mistake) 2 seedlings died because I misted so much day before they fell over and bent their stem, didn't recover, two others were ok. SCHEDULE: 24/0 first 2 wks, 20/4 past 3.5 wks, 18/6 past 4 days.
**Currently in week 6 of veg stage and a whopping 6 inches.
Soil: Schultz African Violet potting soil Plus, even after a ton of research I was swayed into buying this 9 month time release soil because it had everything I was looking for, (perlite, sphagnum moss, composed materials, and for flowering plants it said!, seemed I hit the jackpot)
Environment/Closet: Terrible location but it is all I have. I have a walk in closet, which i tuck my plants (now plant) behind a dresser. Mylar covers 3 sides and a fan blows under and accross my 400w HPS. there is very poor ventilation because I can't do anything to wall/door. I leave for approx 5 hrs tues and 4 on thurs the heat builds up from 79-89 to 95-107. Humidity drops from 47-58% down to about 30-38% I mist average 1 time a day, ussually when i get back and they are hot.
**1 plant left
Containers: for the past 6 weeks of seedling/veg. stage they have been in 6" pots. it is now six inches and I transplanted it into a 12 inch 17 qt. pot. I noticed the roots on the bottom and they made markings on bottom of pot. Nothing like a root ball but a few hairy roots on bottom and sides. Because I decided to rip out the other teeny plant and I didn't want to replant my good one again to fit better in the center, it sits with the stem 4" from the side of the pot. Stupid to put them both in the same and then just remove one but I figured all hope was lost. Will being close to the side hurt the growth?
New Soil: In the new pot I added MG "Organic Choice potting mix", it is totally natural and completely unlike the original soil. I assume this is bad
Food: after the transplant last night, tonight I added more soil to fill up the pot and I gave it a drink of Schultz's 10-15-10 plant food plus. dose says 7 drops/1qt. water, I did, 2 drops/24oz. of water. We'll see how it looks tomorrow. I also moved it a bit out of direct light.

What I think could be the PROBLEMS:
This is what my research tells me what could be wrong, let me know what you think. Take a look at pics to see the yellowing/curled under and 1 set of hanging leaves.
1. Soil, time released is not the answer
2. pH looked to be 7ish when I started, maybe slightly higher
3. Nitrogen deficiency from root lock out caused by a pH?
4. Head stress, this is definitely a major reason I think
5. over ferted from time release
6. 6" plant in about 4-4.75" of soil (root bound maybe)
7. Poor soil breathing (3 holes, should I have removed the water collector to add 3 more holes?)

Thats everything I'm pretty sure. If you read all that I really do appreciate it and would LOVE some feedback.
Thanks!!!!!

shoot, I'm on my gf's comp and can't do the pics just yet. My mac harddrive just crashed and its will be a couple days.

I am new to growing myself. I have only 3 grows under my belt. Sometimes we can kill them unintentionally with kindness. It appears that there was never much consistency in your grow. It is hard to pinpoint a problem when things are constantly changing. There are plenty of folks that have space and location issues that still manage to grow successfully. For everything we do, there are many different ways to accomplish it. Creativity reigns supreme in growing. There is also such a thing as starting out simple and sticking to basics. I think you need to spend some time in the GrowFAQ section of the site. My first grow wasn't great but it was successful. I did so by keeping it simple.

The first thing you need to do is stabilize your grow envoirnment. This would include lighting, temp, grow medium, fertilizer & humidity. Sometimes, because of limitations, you have to be creative. Do a search for closet grows and see how others have overcome that same challenges that you face.