Doing electric hub motors is going to be the same as doing a Bi-Drive bicycle.
The question is are you wanting to do FwD, RwD, or AwD?
Personally I'd recommend RwD with secondary controller to the front pair that can be switched on/off for extra power on demand especially for big hills.
Most of them are fairly PnP, so I'm not entirely sure what you need a diagram for specifically. It's definitely best to get matched pairs, its not good to mix and match on account of different connectors and wire color code systems.