It sounds like your plan only includes carbons(browns) and no nitrogens (greens) to help it all break down and feed your veggies. Start saving kitchen veggie scraps, potato peelings, limp lettuce leaves etc and visit nearby coffee shops for coffee grounds(filters fine) to mix in with your leaves. When I built my beds I had access to bulk mushroom compost and it was a great filler...had a really nice garden my first year. Do a search on this forum for sheet composting and lasagna gardening...you should get some good advice.

If you get the soil built up before mulching then the mulch, unless it is stones or something similar, will contribute to the fertility of the soil so additional "fertilzier" is seldom needed. Each year add to the mulch that is there some compost and mulch over that and the soil fertility will be maintained.

Liquid fertilizers will leach through. I use bunny poo tea.

Otherwise- a layer of greens or scratching back the mulch to apply will work (then rake it back in place).

Thanks very much!