Smaller tanks are much harder to maintain. It's possible to overdose on nutrients if water changes are not kept up. I think the wisteria problem was due to lack of dissolved carbon (CO2) and light.
1) Go DIY YEAST CO2, for a 5gal this method is ideal. Get 2 bottles going.
2) I would get a full spectrum fluorescent T5 or two 6500K, 1600lumens, 26watt CFLs.
3) Ludwigia repens, aponogetons, and wisteria are great starter plants.
4) Schools of neon tetras, guppies, celestial pearl danios or other small fish. Might want to try 3 pygmy cories, 2 otos and a female betta. A nerite or some trumpet snails help also.