Haha, I'll try and not to disappoint you then! I don't know everything yet but I'm getting there
You could certainly have different kinds of shrimp in one tank, and yes you're right about the Ghost Shrimp. They actually have claws and will use them if they want to, I've heard they can be a bit territorial as well, which isn't what you'd want.
I think a plant grow out tank would be absolutely wonderful for your shrimp! I do suggest having at least a few Marimo balls and some Dwarf Hairgrass if you can, I know many shrimp absolutely love to have those! But any and all plants would be great!
I'm also not certain if shrimp have specific water requirements as I've never actually looked into it. Oh, just looked and different shrimp do have different requirements lol. Here's a wonderful, wonderful page on all different sorts of inverts, cardinals were the first to pop up so here you go: http://www.planetinverts.com/Cardinal_Shrimp.html
Yeah I still don't know about the frogs, I've never had an interest in them so therefore I've never done research on them lol.