It sounds like everything is set as it relates to Centrify. At this point you're basically dealing with a Samba configuration challenge.
The way to verify if the IDMapper is working as expected is to map a share to your samba server with an ADuser and create a new file. If you look at the output of "ls -l" the file should resolve to the Centrify-provided identity. You can compare with the "id <username> " output.
Have you checked the Samba forums?
P.S.: After looking at the versions, it seems you're behind on the version of the Centrify software (5.2.2), the current version is 5.3.1 and that has been tested with the adbindproxy package that you have. That's the only odd thing I can see.