Glosso, baby tears, and micro swords do fine emersed. Not sure about how they would fair as marsh plants, but I'd assume that if they grow emersed, they'll grow fine in moist soil.
As for ficus repens, I periodically chop mine down to its nubs...always grows back (and fast). And my soil is VERY moist...
Also, I've had great luck with some sort of common clover...it grows low and thick given decent lighting. Doesn't mind the soggy soil...spreads very fast.
For more options, check out www.blackjungle.com
-- they have a bunch of suggestions.
From what I have read and experienced, *most* aquarium plants will do fine emersed or in a moist environment. After all, most aquarium plants are grown emersed...I think its cheaper and easier (?). You can always pick up a few aquarium plants and try it out...be prepared for some "uh oh, I think its dead" moments. Never say die...let them do their thing and hopefully they will adjust to the new environment.
As for the moss--how are you growing it? Did you take clumps and stick them in or did the moss grow (naturally) on the substrate? I find its much easier to maintain if you let it grow in on its own.