re-reading this
thread, my experience runs counter to the original post: both red mulberry and black walnut are
native in my area and they frequently happily grow in close proximity to each other, with no noticeable ill effect on the mulberries. similarly, we have some mulberries on M. nigra rootstock between walnuts (it’s primarily a nut orchard), and they seem fine with the situation too.
with the hawthorns, our
local native ones (not %100 on ID) frequently grow in the shade of black walnut overstory and seem happy enough (though in the shade they don’t fruit much at all). that said, other roseaceae relatives of theirs have definitely struggled from their proximity to walnuts.
no experience with azarole specifically.