I have a very similar problem, but not with PloneArticle, but my own
archetypes-based content type.
I also get the 'Could not adapt' error:
ConfigurationExecutionError: exceptions.TypeError: ('Could not adapt',
<PloneArticle at >, <InterfaceClass
Products.Archetypes.interfaces._schema.ISchema>)
There's nothing fancy with my product, just usual archetypes stuff.
Apart from making my content types implement IMirrored, is there anything I
need to do to make CM work with my content types?