I've heard its easier to plant some species when there's no water in the tank, and then slowly adding the rest of the water. I imagine that if you were to keep the 6" of water in there it would be alright and shouldn't give you much trouble.
I've been transferring tanks and fish ever since I started planting, so I've never had the luxury of being able to slow start an aquarium setup, I always rush through it. So my tanks are usually being flooded and finishing up a cycle by the time I'm adding plants. Let me know how the shallow planting goes. I've looked into a few tweezers and other tools for my tank, something a little less invasive than an arm and hand rolling around. It would probably help me get the delicate stems and root plants in deep enough without disturbing so much substrate.
Corys are nice additions, I currently have some Juliis in my tank, I like them alot. They're always busy rolling around the tank, I haven't seen them much since the big overhaul, but I think they're hiding in the thicker sections of stems. Who knew a fish could still hide in a 3ft tank.
I'm not a shrimp guy yet, so I'll leave that up to someone more qualified in that department.
I'm also realizing that I don't think I put enough substrate in when I started the tank, because I'm having trouble keeping my rooted plants deep enough.
Planted 40B - 2 Angels, 3 Swordtails, 5 Julii Cories, 10 Harlequin Rasboras, 3 Otos, 1 Clown Pleco, and some Ghost Shrimp.