I use lettuce year-round in zone 8. I put it under squash and corn to keep down weeds. When they are about to go to seed, I just pull them up and let them lay on top of the soil as mulch to retain moisture as summer heats up in August. I use them as attractive borders where I can't weed easily, and they are great at keeping out weeds. In the fall, I grow a crop for food and extra to throw into the compost. It breaks down so quickly, so I can use the compost in February, when I am ready to plant early spring crops. I also really like sweet peas for the high nitrogen and fast decomposition. Another poster mentioned radish seeds for cover crops. I needed to break up hard soil, so I threw in some daikon radish seeds. They did an amazing job. Root vegetables are a great cover if you are interested in no-till gardening. Just keep topping with compost and let the roots and worms do their job!

That 4 inches of shredded leaves may be a bit much and could keep the Rye and Vetch from growing, but that depends on how much growth they had before the leaves were plunked down.

Did you do it? I think the November timeline would have been fine. I was going to do the same with barley a few years ago and missed the November window and planted 1/23, and it did great. I often use winter rye as a cover crop and I found that the winter rye creates a much greater root mass than the barley. Due to that, I would say the winter rye is much better for soil development than the barley. Please let me know what you decided and how it worked.

Winter peas are my favorite cover crop here in zone5 (though some claim it's 6 now). Generally germinate quickly and easy to remove in spring. Another that I like is winter rye. The downside is that it can be a chore to remove if grown too thickly. What I do with it now is make narrow strips. Looks cool during the winter and reasonably easy to turn over in the spring.