So I haven't been pushing the lawn care aspect of my business very hard, and probably won't until next year, but I have been doing a small amount of work on some lawns(been focusing on design/install). Mostly I've been topdressing with compost both in the spring and fall, aerating and seeding as needed. The major issues with these few lawns that I've had is grub issues and some weed pressure. Otherwise, the lawns have looked pretty good with these inputs. Moving forward, I plan to introduce maintenance along with the care. My feeling is that for an organic program to work well, the maintenance side of things is very important.
On the issue of enough food for the herd, by mulch mowing for almost the entire season, would this provide enough additional food. I will most likely stick with 2 compost apps per season....though I am still working on the timing of each. The leaves will be mulched until we have the major leaf drops where I will mulch them pretty well, and then bag whatever gets sucked up.
Spot seeding in spring and fall as needed should help to maintain the turf density.