I'm not sure I understand what you mean by configuration.
I have multiple MT4 installations (all running in portable mode but that is because I need them to run from external media).
Each installation runs a different account. There is nothing more complicated than that. I can open them all up simultaneously without any apparent conflict.
To give you RAM/CPU figures would be rather arbitrary as it depends entirely on what you're running through each terminal.
The markets are shut at the moment so the terminals aren't really doing anything, but here is the CPU and memory screenshots with 4 terminals open:
You can set affinity in Task Manager if you want to (note: optimization only uses a single core AFAIK).
Again, doesn't really help. All EAs have different levels of intensity.
I suggest you run a few instances and see how you get on.