Im no expert. But Im in the same spot as you and have spent alot of time researching this online and are as confused as ever.
Im leaning towards the GR5 w/Kontrol floorboard to simplify things. Then it can be run directly into a Tech21 PE60 or Roland Cube, or even a pair of them for stereo set up. This way no mixer is needed. But you can incorporate a mixer if you need to. Or with the Kontrol board you also have a headphones option at hand.
Or you can also run these into a single or pair of powered FR studio monitors.
Mainly you want the amp/studio monitors to be as clean sounding as possible, so they dont add any flavoring to the signal. To get me started, Im going to try to make mine work with my MIII or Bronco40. Seeing that I already have them, and both are capable of amazing clears.
There are other methods of using the software with a basic interface and mixer. This is where there appears to be many solutions. Some good, some bad.