Hey there Athalay,
We have someone currently working on this issue for the next version, to be released November 15th. He's almost done, perhaps you'd like to get in touch with him? If you email firstname.lastname@example.org or hang out in the #forge IRC channel, I can put the two of you in touch. It would be good to compare what each of you has done so that we can get this fixed as quickly and as completely as possible in the Forge core APIs.
As far as answering your questions:
1. You cannot include forge implementations in plugins - this is disallowed. In order to do this, you would need to copy all of the source files into your plugin project (or create a new maven dependency with a different groupId,) and include the corresponding Eclipse JDT dependencies in your POM file as well. This is a known limitation of Forge 1.x that we are resolving in Forge 2.x.
I hope this is helpful,
My version only supports the use case of our current project, so i don't think i could help.
I'll be waiting patiently .
Thanks for the fast reply