townhouse patio suggestions

Hello,
we just moved from the suburbs into an old brownstone on the Upper West Side, and the patio/garden in the back is ours. I'd like to gradually redo the landscaping with a permie-attitude - thinking about dwarf fruit trees, etc, but have no experience gardening in these kinds of containers. It's the kind of house that I'm hoping could be a kind of sample of what's possible in the city. We're doing some work on the inside of the place, so this isn't the highest priority, but I'd like to sneak in small progress between other things.

I plan to take down the second tree (it's the same kind as the mature one) and put in a large native shrub, probably elderberry, but open to other suggestions!

Also really want vertical fern gardens, moss gardens, etc, any ideas to cover the bare brick walls with something alive? I've attached pictures of the various parts of the back garden.

Also, any advice on mosquitos? They made the patio unusable in August and September. We cleaned out and treated the drains (the Bt bits seemed like the best choice), and I think removing all the ivy will help, but would still appreciate any other suggestions. We obviously have no control over the neighbors water, etc.

Any advice or resources on damage-free vertical gardening? urban fruit production, especially with rats in the neighborhood? semi-shade container gardening? drainage and pest control? attracting native pollinators? We're very close to Central Park and I have been thrilled by the wildlife there - much more diversity than the suburbs, actually.

Any folks doing any kind of urban permaculture in NYC I could check out or connect with?