The plans are not yet available. The aircraft was completed and inspected in April of this year (2015). It is doing occasional test flights to my knowledge. He has made a few modifications and there has been no timetable posted for when the plans will be made available.
To my knowledge, there are a few parts that will be interchangeable. I believe 28 wing ribs from the double eagle can be made ahead of time. The wings as a whole are very similar, but the cabin eagle's folding wing options changes the attachment and control mechanism. I believe the engine mounts and landing gear brackets are the same. The control stick may also be the same.