Hi psussi,
MDD animation export/import: Not to my knowledge.
PLA (Point Level Animation) is pretty much the same inside the application, available in Cinema 4D.
It is supported by Alembic and FBX, for example.
One can use PLA in the Animation Clips, but then again, you could use joints there and keep the file smaller.
MDD or PLA is relatively hard to manage; with greater mesh density, this becomes more obvious.
Example file
https://www.amazon.com/clouddrive/share/tqkEv3dnPw6a20W5zj9CT5FkCUcZrvbb37EKmHUSBFM
The PLA animation was exported and imported back into the file.
As a side note:
I would need to see the files to suggest PoseMorph (absolute) to suggest this path.
Let me know if you like to have an upload link; I’m happy to set one up.
(Dropbox, Amazon, Google, Apple, Adobe, Wetransfer only, thanks)
My best wishes