Just thought I'd update:
The tub is planted and the water area is cycling. I'm planning to add a nerite snail (the eggs will add a tidal zone authenticity, I think), then eventually try some mosquitofish in there.
The plants (left to right) are the black mangrove (grown from sprouted propagule), sea purslane (collected from a S. Florida beach), and in the buried plastic bowl up top, holywood lignum-vitae (Guaiacum sanctum), which I grew from seeds collected from a specimen growing in a friend's yard in the upper FL Keys.
For substrate, it's a mixture of Carib Sea mineral mud, generic garden topsoil, and coarse aragonite, topped with a mixture of sand and aragonite.
I plan to modify the shoreline a bit once the sea purslane roots start to hold it together, probably will add some larger chunks of coral/limestone around where the airstone is.