You should have no problem with the names, if they are all linked up to the same battle.net account. I wouldn't think you'll even have to enter in a name. I'm not sure on that because i merged mine.

I five box on something similar to your machine. However, all my slaves have their graphics settings on low. It runs fine obviously not ideal especially compaired to other setups in the community. But, It is what it is.

Definitly, Make sure your raf is setup correctly. Littleburst suggestion is exactly what you're looking for.

Have fun.