A/C repair trouble-shooting

[zooklm]

I had previously posted a few weeks ago on my 87 300D. I injected dye to look for leaks. Only place I could find was on top of compressor (see arrows on photos).
The back of the compressor leak is between the manifold and compressor and I know how to change those. The area on the top look like it is comming from between the adaptor (that has the manifold attached to it) and the compressor. My question is this complicated to replace the seals (assuming o-rings). It appears that the compressor will have to come out (yes - no) to remove the top plate.

Any particular tricks to removing the compressor?

Should I also replace the o-ring at the expansion valve, even though they don't leak?
I also saw a post for synthetic compressor oil for R-12. Does anyone know which brand is best and where to get it?
Thanks,
Lee