Welcome to Permies.
Dealing with droughts is a concern for so many (usually they are followed by a round flood, which only makes it even more challenging).
I think you have
alot of the knowledge already to grow in a dry climate and we look forward to your process and pictures.
So my take on growing in dry climate is earthworks/spacing/catchment area. If a plant normally need 20ft in wet climates give it 40ft if you get, say, half the rainfall. Give the water time to soak in vs sheet off (flatland) or runoff making gullies (steepland).
Drip irrigation is your friend, at least to get the system started. You can also use your greywater too. Mulch
hay they are cheap $5/bale or woodchip, it might be free too. Mulching also cuts down on evaporation. Add
carbon any how you can compost/chop and drop/biochar/etc.
Tree
root take alot of water to get minerals into the tree, so have the tree trade with fungi-roots to get more mineral for less water overall, the
trees will lose out on a but of sugar/stores sunlight but we already have an 'excess' of that.
Ground cover to slowly but surely build soil fertility, soil life, carbon in the soil, etc.