It looks like you might be over-thinking the garden. Perfection is a human construction. Nature is going to do what it do! You're going to try some things and they may work and they may not. That is how you are going to learn. It's fun to get your hands dirty and learn in the processes.
If you do something like Biointensive then you are going to plant a lot of vegetables closely packed on only have your garden and then the rest of the plants will be for composting.
If you are pressed for time and effort you may want to try all perennials so do the work once and not year after year.
You could setup a small
compost area for all your table scraps, junk mail, etc. for your fertilizer inputs (screening the materials so it is all good stuff). Perhaps a worm bin inside for the table scraps and then use that for your fertilizer outside.
You have a lot of flexibility with a garden. If you are running a farm it would be a different story.