... the circled plug in the attached picture is the CPS coaxial correct? And the inner pin each the outer cylinder each count as a separate terminal towards that 10? So pin 31 and this outer cylindrical terminal in the CPS plug connector should be the only combination of terminals with connection, but how low of resistance is considered full continuity? ...
That‘s all correct. The resistance between pin 31 and this outer cylindrical terminal should be below 1 Ω.
... When you say the mounting surface, that is the surface that will be in contact with the car correct? Will any heat sink paste do?
Correct. You could, for instance, use heat sink paste that‘s used for CPU coolers in computers.