Common practice is for the tighter angle to be done by the B camera, which is a practice I've never quite understood since the more experienced focus puller is often on A camera, but B camera is doing the harder shot, focus-wise. So I tend to assign the shots more by which camera crew is better for that angle / shot size.
As for whether A or B goes onto the crane or Steadicam, it just depends on what is practical and whether the Steadicam Operator is the A or B camera operator, if you are talking about a Steadicam shot. For a crane shot, again, it partly depends on which operator you want on the remote head, but also since one tends to leap frog set-ups when having to jump to a crane or Steadicam, i.e. one crew is shooting a shot single-camera style while the other crew is building the camera onto the crane or Steadicam, it depends on which crew you want to keep shooting studio-style while the other is prepping a camera.
On some shows, you have the budget for a third body, C camera in that case, that is set aside just for Steadicam (or crane work), often set-up for Steadicam at the start of the day so it is always ready to go to.
As for telling if the coverage of a scene was shot with two cameras, it generally is easier to tell when, unfortunately, the tighter shots look a bit too telephoto and sloppier, as if "grabbed" at the same time as the main set-up. You can also tell if the lighting is exactly the same with no changes between the two sizes, though that is not a guarantee that two cameras were used.
B camera angles tend to be long-lensed just because it is hard to work multiple cameras up close to the actors with wide-angle lenses and not get in the way of each other or see the other camera -- it's easier with longer lenses to use multiple cameras. But again, that is not a hard and fast rule, it is possible to find ways of working wider-angle cameras closer to the actors, it's just that odds are higher that the second camera will be more to one side, less on the same axis as the first camera.