Anubias doesn't like to have its "roots" buried, it does best when lightly weighed down (not buried) or tied to some rocks, driftwood, etc. So that explains one issue. I'd try it again, Anubias is normally extremely hardy. Oh, and Anubias is a lower light plant. So try to place it in a more shaded area.
What happened to the Bacopa caroliniana? Did the leaves change color or anything before it died?
My Cabomba has always done best when weighted/tied down, floating, or only loosely planted. It doesn't like the stem to be totally buried. It's a plant that doesn't always transplant well so it might have just never acclimated to begin with. I'd give this one another shot.
I haven't kept Myrio in ages so maybe look that one up on planted aquarium websites. Mine wasn't planted very deeply...just enough to keep it down. It was in a tank with just gravel. I don't think it needs anything special so maybe this is a case of an unhealthy plant or maybe a plant that was buried too deep?
Here are some easy plants that would work, see if any are available in your area: Water Wisteria, Water Sprite, Echinodorus (there are a bunch of species), Sagittaria, Hygrophila, and other Anubias you haven't tried. If you have any shady sections, java ferns could be planted there. Those guys are the definition of hardy, ha.