Worked on my 2006 and 2012 MBPs. I cleaned out the rather noisy fans in the 2006 MBP using some compressed air and while I did dislodge a big clump of dust, it doesn't make the fans any less noisy. Might try and replace them with the ones from my non-working 2006 MBP. I also attempted to fix the Python issues with PPCMC, but realized that I don't have the skills to do things like compile my own version of Python. What I did instead was follow post #4 of the thread from the PowerPC forum (
https://forums.macrumors.com/threads/ppcmc-updated-with-python-3-11.2380642/) and followed cellularmitosis's instructions. I also replaced the Intel edition of PPCMC with the PPC Tiger one from my G5, which I copied over via TDM. That copy already had the updated files from alenu's zip file, since I had already updated my G5's PPCMC installation. I tested out both the downloading and file converting functions and now PPCMC is working again for me under Snow Leopard.
As for the 2012 MBP, the arrival of the M2 Mini in my collection has freed me to go older when it comes to OS X on this Mac and so I did. After much debate, I decided on using Lion on the 2012. I like having the 3D dock and Lion gives me a wider net of compatibility with older software compared to, say, Mavericks. For example, EyeTV 2 is broken under Mavericks, but runs fine on Lion. Even though I already run old apps like EyeTV 2 on multiple other Macs that are much older than the 2012, I enjoyed installing them on the 2012 and I like having the option of using them on that Mac. At one point I had a triple boot of Lion, Windows 10, and Ubuntu going on, but I fell out of love with Ubuntu when it prevented me from booting into Windows 10. Picking the Windows icon in the rEFInd menu would take me to a GRUB rescue screen. On top of that, the Wi-Fi issues reared their head again and I had a painful time trying to replace LibreOffice with OpenOffice. So, I deleted Ubuntu's Swap partition and formatted the partition that Linux once resided on, so I now have and empty 330 GB FAT partition. I had to boot from my Windows 10 installer USB and go into a command prompt to fix the boot issues caused by GRUB. I then used Windows for a bit and I can't believe I am saying this, but I actually prefer using it over Ubuntu on this Mac. I don't know what I will use the third partition for now, but I guess it's good to have on hand in case I ever needed to put a newer version of macOS on this Mac like Mojave.