"incompatible logger" error is the Green Dot logger issue where newer VP2 consoles must use a so called new Green Dot logger. There is really nothing wrong with either your 6555 or VP2 console it's just that one being old and one being new Davis made it so the old Logger would not work with the new VP2 circuitry. In many ways it's a burden all Davis users have to endure as a backslap on the cloners.
If you want to use WeatherBridge with the VP2 then new logger, if you want to use Weatherbridge with the Vue then use old logger. The logger has nothing to do with additional sensors, that a function of the ISS or Console. An new 6555 will work in the VP2 or Vue without problems.