I've been looking to get a edge as well..
with the led's, I'd say you are in low light because the height of the tank..
the baby tears will be very very very slow if doesn't melt. Probably any rotala will grow slow if it gets good light from the led's.
As for pennywort and Pogostemon stellata..I've never had them, but google says Pogostemon stellata needs intensive light and co2 - so no, but dwarf pennywort should grow ok.