I'm not Episcopal so it is okay to just say it's none of my business. That said, instead of fighting over the building, just split it between a liberal and conservative congregation.
Have two congregations share the building with a neutral committee managing and scheduling the facilities. Sunday schedules should be rotated each year to prevent one congregation from monopolizing "prime preaching time". Let each congregation pay half towards the building maintenance and let each congregation pay its own clergy. Require the diocese to support the congregations in proportion to each congregation's record members. Then let each congregation survive on its own.
I am not episcopal either, but I think you are missing the point. It would be like a divorced couple living in the same house.
That would be fair, but there is no splitting. What these people have, unfortunately, done is raise the money, built the building, turned the title over to the Diocese, and are now being evicted.
I'm leaving the Episcopal Church. I'm not even writing an Opus.