This is outside of my expertise. I have always done things the reverse of you: I use a full local install of Python and make system calls to generate figures using MRIcroGL. This approach is documented here:

  https://www.nitrc.org/plugins/mwiki/inde...

In my experience, recent releases of operating systems have intentionally hampered the ability of graphical tools to use scripting languages to prevent malware. Older versions of MRIcroGL used the system python to do everything, but this is now either deprecated or explicitly blocked depending on the operating system. It may be possible to set the 'PyLib' variable of the MRIcroGL preferences file (click Advanced from the Settings window) in some Linux distributions, but your mileage may vary.