Coverage configuration = TX Diversity. By definition.
Your connectors configuration is fine. One X-Pol antenna will transmit both Tx signals (one from each port).
UL will be too weak, and the cell coverage will become “uplink limited”. To counter this, you must either install TMA or install a secondary X-pol antenna. The latter allows to get 4-Rx-Div.
Cheapest solution is the TMA, definitely 🙂
You can leave with a UL limited cell, and the coverage gain compared to a capacity mode is still interesting. But if you really want to maximize the coverage (maybe not on all cells, but on the most critical?), then think about adding a TMA.