80F might be a little warm for angelonia, I suppose it could delay germination. When the sowing suggestion says 'light', that is more of a suggestion referring to sowing depth, whether to cover with soil or other medium or sow on the surface. It doesn't mean the seed trays need the hours of light as would be required by seedlings which has the disadvantage of the soil/medium surface quickly - thus the seed - drying out. Put your flats under artificial light after germination, just a very few hours of light of some kind during the day is enough prior to the seeds sprouting. One plantsman said in a class I took several years back even a few hours of light once the seed is moistened not continuous light or even daily (meaning moist long enough water has breached the seed coat) can be enough for some species.

"Sow seed indoors at 70 to 75 F. Use low light until the seeds germinate in seven to 14 days and then bright light for the seedlings"

How do I create low light in a dark cellar? Perhaps I could raise the ratchet carabiners on my lights so instead of being inches from the flat, maybe 2-3 feet from the flat?

What could be said for the seeds themselves (since I depleted my suppy). Are they ruined? Or still waiting for the right germination conditions?

The assumption is that you purchased the seed, it wasn't collected? You could have just received bad seed. The other thing that comes to mind is that you "cooked" the seed, or the seed dried out after it imbibed water, then died.