I have noticed that you wrote most of the facet stuff in the mentioned package. I try to create a new facet headless via WTP to a new project.
I add the nature with WtpUtils.addNatures(project); I like to create a dynamic web project with only a base facet like IJ2EEFacetConstants.DYNAMIC_WEB_24, but even trying 2 days, I fail.
Do you have a hint, how to do this with only a few lines?