Cory Options

Hi everyone!

My last few guppies are about to move to fishy heaven and I'm thinking of adding corys to the community tank. It's a 40g, 78 degrees, 7.5pH, 150ish gH, 80kH, 0 ammonia/nitrites, 50ppm nitrates. Stocked with 1 pearl gourami, 1 blue phantom pleco, 5 threadfin rainbows, 9 cherry barbs, and 13 gold ring danios.

Couple of questions on Cory's:

1) which dwarf/pygmy species would thrive best in here? I read up on pygmies but am concerned about my tank being too warm

2) anyone keep corys and specifically ble/green phantoms? I'm worried about the corys annoying and competing with the pleco

3) I'm still trying to get plants to work well, latest batch still acclimating. Anything specific I need to get if I'm looking at corys?

4)Any ideas for other improvements I can make?