I know of at least one "green" hypo line that for sure is compatible with the main hypo group.
Almost all of TSK's hypo mojave and just plain hypo's trace back to this female now listed as a green hypo:
http://thesnakekeeper.com/index.php?...po01f&page=lin
I think she is the import they used to call "extreme hypo". I used to have a male pastel het hypo who got his hypo gene from a TSK hypo mojave and I produced a really nice looking hypo in 2009 crossing him with a possible het descended from what I think Brian Sharp used to call yellow hypo. I've since produced other hypos from that het girl bred to a cinnamon het for an unspecified hypo line. So if your green ghost traces back to TSK (seems to be very common in CA and the west) I would expect it to be compatible with the larger ghost group.