There are no 64-bit Mac OS X kexts for the Intell GMA 950, only for the GMA X3100 even then they are unstable.
This is incorrect.
I have El Cap on a 2007 Mini. Required a USB 3 card but it works. And using the 64bit GMA950 kexts makes things better. Not perfect, but better.
To the poster above me, I'm not sure that MBP has socketed CPU, if it is soldered, it is staying.
There are threads in this section where you can get info on Mini flashing to 2,1 and threads in the relevant OS sections on getting the OS installed.