It seems to me that the majority of your programming work is going to be developing the interface between the AD-AHRS and your system, and this would indicate that most of the work would be fairly low-level. It seems as if you'd be better off with C or C++.
There's always the possibility of splitting the workload between Python and C, with Python handling the higher level control structure and C handling the low level interfaces. Tools like
SWiG make it rather simple to integrate the two languages.
That all said, there's no point in using a circular saw just because you have one lying around. Python may not be suited for any part of this project.
I suggest researching what open source libraries are available to communicate over PC 104, and in what languages they are in. The tools that you require will likely shape what language you will end up using. Start by building up a general interface to the AD-AHRS and once that is done, evaluate your options for displaying the data the AD-AHRS returns.
Both Python and C/C++ have plenty of graphics libraries, so you shouldn't want for tools on that end, at least.