How far from retaining wall should I plant trees?

I want to plant more fruit trees on my hillside and I plan to keep them trimmed back to be small. Currently there are avocado trees planted kinda center of the hill.

How close can I plant trees to the retaining wall without risking damaging the wall?

Also if you have any favorite fruit tree recs. Would love em. Zone 10a. Half the yard gets some winter shade, the other half is full sun year round.

Ps. Im also digging some swales now/planning on planting companion plants.