Re: jaxb2-maven-plugin 2.0 not available on central
It hasn't been released yet. Unfortunately the mojo doc page doesn't reflect when/if something has been released (there for that page says v2.0). However, if you look at the mojos page  it will/should reflect what has been released.
During the vote of the plugin I've found some regressions, but I don't know what the release manager for this release wants to do (cancel or promote anyways).