I've not yet tested any of this, but I noticed: py2exe/py2exe@43ee68b specifically from py2exe's changelog:

Remove build_exe command line interface. Please use the py2exe.freeze API.

In our cmdclass.py code we have:

    if 'py2exe' in sys.modules:  # py2exe enabled?
        try:
            from py2exe.setuptools_buildexe import py2exe as _py2exe
        except ImportError:
            from py2exe.distutils_buildexe import py2exe as _py2exe

Which will fail if used alongside py2exe 0.13.