I agree that the real alignment is probably at fault. Correcting the front end has now exposed alignment problems with the rear end.
Alignments don't require the removal of the steering wheel, so I doubt that the wheel is off-center.
However, if the steering wheel was removed and installed incorrectly, then the steering wheel can be removed and reset to the correct position. The steering wheel is attached by a large nut, and the steering shaft is splined. The number of teeth on the splined shaft allows you an (almost) infinite positions to set your steering wheel.
I have done this succesfully on some former vehicles I've owned (when changing to a custom steering wheel), but I don't know anything about the proper removal of the SRS unit mounted on the wheel. Best left to a professional.
Hope this helps...
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car