Hi
You can create a "Approved" notification to be sent out at the last stage of the path, and apply the custom messages to that notification per respective last stage/path.
However, if you are planning to use the %PROVISIONING% or %PROVISIONING_WITHOUT_PASSWORD% variable within any of these custom notifications, it only seems to work in the notifications sent out at the end of the request/ AR Close set up in the Global section (screen 1 in MSMP).
There is a note at the end of the SAP note that describes this limitation:
Remark: Class CL_GRFN_MSMP_BADI_END_OF_PATH implements following logic:
At end of each path of Access Request, workflow email will be sent to msmp agent GRAC_USER using template GRAC_AR_CLOSE
Hope that helps.