Pull the weeds, kill the Bermuda grass, make sure the Bermuda grass is truly dead and gone, and then underplant the palms with Agave attenuata (soft, no spines) and a few Aloe striata (Coral Aloe is the common name), or just mass-plant with Aloe striata. Ultra-low maintenance, no litter, little water required, won't interfere with palms.

Exactly. Use blue Kalanchoe "fingers" or Cotyledons- they come green,and even pure white..all have very beautiful flowers.

Bromeliads are low effort easy to grow..but they do need constant light waterings. They do however fit perfect with palms. Try Aechmea blanchetiana..a gore-gee- us looking big brom.

Do you plant the bromeliads directly in the ground?

Yes. Easy as pie. You can dig them in,or sort of lay them on top and surround with bark- they will cover that pretty fast. Some are fast to send out many pups and can cover ground quickly. Fireball is one of the best and its hybrids that add variety. A good and big and fast brom is Aechmea caudata..very hardy although its a generic green on its 3-4' height. Great bloom though.

Two or three trailing lantana would also fill in pretty quickly and flower most of the year.