Can I go ahead and put one more round of fertilizer down in November before winter comes? I use organics so could use soybean meal or alfalfa.

Yes, but depending on temperatures don't expect much until spring. My last round of organics went down nine days ago and I don't expect that much of that will tap out until temperatures rise in March and early April.

Decay continues at any reasonable temperature (even down below freezing due to the cryophiles in the soil), but it's very slow under fifty degrees soil temperature and extremely slow under forty. Hey, stuff goes bad in my fridge, which is set at 36.

Should I use Winterizer at the time I overseed? I've read that people use that instead of other things around that time? However, is it organic and where do I purchase it?

Personally, I'd wait until after the typical January thaw just to make sure that the seed doesn't decide to sprout on you and then freeze out. For KBG that's less of an issue since it takes forever to sprout, for ryegrass much more as it sprouts fast.

Winterizer is not an organic (see above; lower temperatures render organics mostly useless during winter). Technically, it's also the wrong mix (midrange nitrogen, midrange potassium, no phosphorous).

Either don't fertilize and do it in spring, or don't fertilize at all until your normal one. Seeds contain everything they need for the first bit, and if you feed organically you have some nutrients charged into the soil.

Thanks so much for your help! I appreciate it.