about #3 then AS7.x runtime does not include the implementations currently - just the necessary for actually compiling.
Mainly to avoid collision at runtime (i.e. junit tests etc.)
With the source lookup feature in place and m2e-wtp automatically removing this classpath we might be better of actually including the runtime but then comes the problem you just witnessed: multiple versions of the same jar...feels like we can't find a way that will work well in most cases..