Great thread here, your plan of what to plant over the first three years looks really good, avoiding the temptation to go for food/fruit off the bat and choosing wisely the drought tolerant N fixers. Leucaena is a staple of my plantings due to fast growth AND drought resistance. In the animal buffet though it seems to be first choice. I take an 8 litre bottle, cut off the base and stick it over the seedling (with lid off). This retains humidity and protects from rabbits, goats and lizards. Do not underestimate how much damage lizards can do to small trees, they need to eat too, and can get thru mesh. They can also tunnel but only if you make it really easy for them. About growing leucaena seeds... I take the seeds from pods that are just starting to split on the tree, and soak them in hot water. Half fill your vessel with tap water and then top up with water from freshly boiled kettle giving you a rough temp of 60C which I found works best. Leave them in the water for 24 hrs. Once planted, they will germinate as soon as the temp is in the high 20s C.
A tree noone has mentioned yet is gliricidia sepium. It is more drought tolerant and fast growing than any other tree I know of. And finally yuccas... actually a cactus rather than a tree, these don't grow as fast as the N fixers but are super drought and wind resistant and can form a very effective eventual security barrier. Mind your eyes on the leaves tho so be careful if children about.
Also like your fruit tree choices. I would add fig (as already mentioned by others), and consider moving moringa into year 2 unless you are prepared to devote quite a bit of water to them. Moringas aren't too great in the wind either, especially in the first year. Maybe grow a couple at the outset in a wind protected area to get started and give yourself a source of fresh seeds for year 2.