Have you considered the Mediterranean breeds? Breeds like Leghorns, Minorcas, or Andalusians would probably be good choices for a hot climate, and are traditionally known as good layers.I'm curious about what breeds y'all think would be best for a hot climate...Eggs will be primary goal with meat secondary.
Leghorns do come in other colors than white, although the other colors probably don't lay quite as well as the white ones (since commercial breeding has focused so much on the white ones.)
Any chicken can be eaten, and even small chickens tend to be bigger than the quail that some people raise for meat. Even the dual-purpose breeds you named will look small next to a Cornish Cross chicken (meat bird from the grocery store), so it's just a matter of how small you are willing to go.
I think that is a very good idea.You could try ordering several birds of each breed you are thinking of, raising them for a year, and seeing which you like best/which are doing best in your specific situation.
When I have gotten several breeds, my very favorites were usually not the ones I expected to like best.