Did your power locks work before you switched out the MCU? If not, it could be the actuators. They fail all the time, so the fact that both don't work wouldn't eliminate both actuators failing together as a possibility.

No idea on the cruise. But I did a search, and a lot of threads that detail the possibilities, between this forum, club ep3, and H-T. So there's some decent info out there. One of them does mention fuse #4 as one of the possible culprits.

Good luck.