So I ended up going with effectively a 5-1-1 mix. I already had some miracle grow all purpose slow release fertilizer around (9-4-12 analysis), so I went with that instead of an osmocote or something of the sort.
The plants were not real happy. Many turned a little yellow within about 3 days, and some of the tomatoes got burned. I figured I probably gave them too much fert too early, since most only had 1 or 2 sets of leaves, and they were growing so slow with the ambient being around 69 degrees. Talking to my father (who is an agronomist and worked in the field for 4 decades), it also sounds like the "slow release" miracle grow is usually not the slowest to release, and a significant portion of the nitrogen is released to the plants on first watering.
I "built a reflector" (read: taped aluminum foil around the light), put some towels under the tray to hold some heat in, and got the ambient to around 77.
They seem much happier now. They're regaining a lot of their color, and seem to be growing ALOT faster.
Much happier plants. I learned a valuable lesson, and that is not to go cheap on things, especially when it comes to soil. Someday i hope to be in a position to have my own compost, but until then ill just have to make do with what i can find.
Thanks for all the help so far, everyone!
