Why not transfer plants now? They'll certainly help speed up the cycling process and make it easier to add critters when the time comes, as they'll be less likely to get uprooted and moved around as you're working in the tank.
The substrate looks a bit shallow for anything tall and rooted. It'll look great once you get something in it, though. It'd look really great with a small piece of driftwood covered in moss.
My vote, as a shrimp nerd, is for shrimp!