No, that´s basically it.Nice. I watched the video you posted as well, and things do seem snappier. VLC and Maps never worked with Yosemite or El Cap on the 4,1 either. I use Movist on those installs and it works great. I haven't tested mkv files, though.
I'm going to be attempting an install today. For your installs, you just clone a working supported Mojave install, replace the prelinked kernel with yours, replace the kexts, rebuild the kext cache, and go? Or are there steps I'm missing?
Wait: You´d better take a pre-patched (dosdude1 patcher) working install (from 10.14.3 upwards), as there are other obstacles (like the telemetry plugin) that are not served by my kext findings alone!