Shrimp would be ok, but I believe most (if not all) crabs or crawfish will eat your fish. I'll mention it since nobody else has - don't mix angels and neons together, in the wild neons are an angel's natural prey. Go for cardinals instead if you want angels with them. The reason for having only one pleco is because they are poop machines and you really only need one. As mentioned above, go for a small pleco (not a common or sailfin) such as a bristlenose or a clown.
I'd either go with:
A pair of angels
8 cardinal tetras or any other medium sized tetra
6 cories
1 small pleco (or 3-4 ottos instead of the pleco)
A handful of shrimp
A pair of rams
8 cardinal tetras or any other medium sized tetra
6 cories
1 small pleco (or, again, 3-4 ottos instead of the pleco)
A handful of shrimp
You could also have a group of small loaches instead of the cories. I don't think it really matters which kind of shrimp you get, either cherry or ghost, or whatever else you can find (just make sure it can't eat your fish! I know some grow big enough to do just that!)