I would just do the poke through the hole suggestion. A few weeds is very little bother to tend. You have most of the region covered, so it's just the holes. This is standard sheetmulching procedure from Mollison.
Fall is a great time to start seeds.
Willows you can grow from a cutting or from just a thought about a willow. You could plant some saplings in addition to seed.
Is there any value in a Cornelian Cherry dogwood wood? that way you could get food as well as weaving material?
By the way, it probably would be a good short-term solution to forage the willow you need, or even make an arrangement to coppice or pollard someone else's mature willows.
I'm biased against trying to keep seeds in the fridge, but I do think it'll be fine.
For nitrogen, the wood chips will initially decrease available nitrogen if anything (debated, but certainly it takes a while before they start delivering nitrogen). You can put your
pee there (my...er, friend...uses a plastic
milk jug, and that can be done every few days.) Otherwise known as Number One Gold Soil Amendment.
If you can bury a few logs of wood nearby the
trees that will break down and supply nutrient.