Fantastic tanks! The plants look great, the arrangements are nice, and the overall effect is very clean.
I've been working on some similar setups myself. I have found that mud plantains (Heteranthera sp.), lizardtail (Saururus cernuus) and swamp dock (Rumex verticillatus) do very well with minimal care. My Peltandra virginica and various Sagittaria species melted and regrew after transplant; I have hopes for them recovering. Eleocharis and Alisma subcordatum seem to have succumbed. I recently got some Lobelia cardinalis, Hydrocotyle ranunculoides, Echinodorus cordifolius, Pontaderia cordata, and Limnobium spongiae that I'm trying to get started.