To answer your question, there aren't any alignment adjustments possible at the rear of the Honda Fit. Here is the reason why:
This picture shows the front and rear suspension on your vehicle. It shows it to be made as a torsion suspension. At the front of the torsion bar are two pivot points which locates the suspension, then there is a spring and and shock with supports the load of the vehicle and dampens any road obstacles. There is nothing there to adjust to correct your issue. The whole setup moves up or down at the tire side while pivoting off the front where it is attached to the vehicle itself. If the road surface is uneven, the torsion bar will flex to provide stability, as well as while cornering.
While this is a very simple, basic setup, it works quite well. The downside is, there aren't any adjustments to be had. There are two things to think about here:
Since this is at the rear of the vehicle and the tires are just being pulled along (these trail the vehicle), you should have a minimal expectation of wear. The front tires will always wear faster because of ever changing geometries while turning.
The only way I can see there being a problem here is if there was actual damage done to the torsion suspension portion or to the wheel bearings themselves. I would bet if there were an issue with either part of this, the alignment guy would have said something when you got it done. At this time, I'm highly doubting there are any issues of this type.