Just thought I would warn you that you are planning to replace your mimosa with another invasive plant. The vitex has been listed as invasive in Texas. If you get enough water to support azaleas and mimosas, you will probably have vitex seedlings everywhere. I would go with the redbud.
Ugh, Redbuds are a lot of trouble as well! They self sow readily and you will soon be up to your eyeballs in little seedlings everywhere. The only think I can think of that could be worse is a Rose of Sharon. One of those bushes will quickly turn into an overgrown hedge if you are not careful. They drop tons of seeds which means you have tons of new little seedlings popping up all season. I mention this because sometimes these are trained into a small ornamental tree.
I think all trees have a positive and a negative to them and it is a good idea to do a little homework before bringing home a tree to find out what is involved in caring for it. Oak, walnut, elm, and maple are popular trees that litter the ground with seeds. Some other trees sucker so you will be needing to schedule clean up time for them or they will become a wandering mess.
I have planted a few Mimosa trees grown from seeds and they are kept in a lawn situation so hopefully we will be able to keep the seedlings in check with the lawn mower. Last year I found out the deer think Mimosa trees are tasty so maybe any wayward seedlings I miss will end up as a snack.