For tracking scale you need two markers. In AE's tracker controls you can select a combination of scale, position and rotation tracking. This should be fairly easy as long as your two markers are never obscured by the models.
This is assuming that you are not digitally adding in the floor, because then you'll need a more complicated approach since you'll have parallax. You 'd need 3D tracking.
In that case you'll need to reproduce the camera movement in 3D space and you'll need a 3D floor layer in AE.
It may seem like a small difference, but 3D tracking and matchmoving isn't all that straightforward to get right.
If you're planning a small push just to get a subtle tension in the shot, you might consider shooting locked off and doing a small push-in digitally. It's not the same but it does have some effect, with minimal effort.
For 3D tracking you'll need markers on the floor too, and not too few. You'll track the 3D camera move in an application like Boujou, Syntheyes (most affordable), PFTrack or Matchmover. Then export the camera solve to After Effects and place it in your virtual set.
If you're interested in these techniques and have time to investigate and experiment, go for it. Otherwise, get someone else to do it or fake it per my earlier suggestion.
If you're going to do the push-in digitally it helps if you shoot at higher resolution than the delivery format. Shooting Red @ 4k gives you some room when you're finishing in HD.