Hi all,
I start my tanks like that too, I don't cycle them, but plant them and add some invertebrates, and then just leave them for several months until the invertebrate numbers build up, some biofilm develops and the plants are fairly established.
At the moment I'm "seeding" them with Daphnia, Cyclops, Ostracods, MTS, Red Ramshorn snails, Asellus and Cherry Shrimps. I wanted to establish Blackworms (Lumbriculus) in the substrate as well, but you can't get them in the UK.
Plenty of other organisms (rotifers, nematodes) will come with filter sponge and re-used substrate etc.
Depends a little bit upon the fish after that, but I've kept several generations of Killis (Epiplatys annulatus) in this type of tank successfully without feeding them (although I did feed the shrimps), and it was a very densely planted 4' tank. Apistogramma borellii was also partially successful, but eventually eliminated all the crustaceans including the shrimps, and Apistogramma cacatuoides was a total failure and ate all the shrimps in less than a day.
I would like to try Corydoras hastatus/pygmaeus, any Pencils, Threadfin Rainbows (Iratherina werneri), Dwarf Badis (Dario spp.) and Dwarf Sparkling Gourami (Trichopsis pumila) etc. I think all micro-predators should have the potential to be successful.
I think that it should be a more be successful approach in a paludarium or terrarium or with a sump refugium, where you can have fish free areas for breeding invertebrates in.
cheers Darrel