The banjo D7 described doesn’t have a 3rd of any kind so it’s neither major or minor. To be a sus chord the 3rd would be replaced with a 2nd or a 4th but they’re not in the chord. So if banjo is being played with a live guitar player is the expectation the guitar player won’t include a 3rd in their chord? As a guitar player I can’t recall being asked to do that but I also can’t recall playing with just a banjo.