I am curious to see how this all shakes out for you. I am essentially doing the same thing but with the BRZ power steering/GR column (I want the telescoping action).
For connecting the power steering motor to the steering rack (assuming your current setup doesn't work), I would look into the BRZ/FRS steering linkage. If you need spline count/diameter measurements let me know.
For connecting the p/s motor to the column, I got lucky. The GR column matches the spline/diameter of the BRZ motor. So, I just had to trim things down to get the motor to land where I needed it to.