My inquiry is about timing a planting with the summer rains of July instead. We tend to be dry in the winter and spring with dry hard soils and the young trees stuck in their root balls seemed very thirsty.
I think it would be worth a try. I know it is difficult to get plants through the late spring dry weather until the monsoon arrives. But if you have a good monsoon season, the tree can get well established and be ready to go dormant in the fall. People get spoiled by thinking that they will put in bare root trees in March and have fruit to harvest that summer. But if you concentrate on getting the tree well established during the first year, it should pay off in the long run.
Just how dense can I put my trees?
Full size trees should be spaced about 20-30' on center. If you have semi-dwarf trees, then you can plant them more densely, maybe 10-15' on center. For more specific recommendations, you can look at state agricultural extension service circulars on fruit trees. Here's one from
NMSU.
Planting more densely can help, as you say, to provide a windbreak and mitigate a late freeze in the spring. If you think SW NM is windy, you should take a trip over to Carlsbad in the spring. Once that wind from your side gets past Cloudcroft and the mountains, it picks up even more speed. The pecan trees can take the wind, but if you wanted to grow stone fruits, you really needed to have a big, blocking windbreak tree, something like an
Arizona cypress.
Should the burm be above or below the fruit tree?
Both can be made to work, but in really arid climates, you would want to have the drip line of the tree right at the berm on the downhill side.
If you want more variety, you should know that you can graft stone fruits on each other. Take your broken top cherry tree and graft some other cherry variety or some plums on it.