I'd say you need to consult with local legal counsel due to the (extended) time period involved.
It's understandable that you were "locked out" by the other owner but as far as being locked out for close to 14 years, not so much. Legal action should probably have been taken much sooner and you would be responsible for reporting any tax due, as well as taking expenses, including depreciation, for the time period during which rental operations were ongoing.
I also am of the opinion that you would qualify for a 1031 exchange based on the new facts you presented (clearly the property was being held for rental use) regardless of the scenario with the other owner. However, you may also be responsible for your share of the depreciation in terms of future recapture.
This is a complicated scenario, and I strongly suggest you consult with a local tax pro and/or legal counsel.
