It will help me finalize the GUI for the plugin selection (with all the supported tags you've got in there, the dialog must be huge). Beside some unfinished things it's looking good.
Some comments while reading the code:
- For TMDB I use the language pms uses to get results (PMS.getConfiguration().getLanguage()). Might probably be better to set the preferred language in the global configuration of the plugin to make it configurable per plugin rather than globally. Not a must, but a nice to have.
- searchForFile should return null. As isSearchForFilePossible returns false, it won't be called anyway though.
 To include required dependencies in the plugin jar which aren't included in pms, you can have a look at this example where the imdb import plugin includes the json library.