NOT POSSIBLE BY FANEDITING
The resistance spy concept isn’t a new idea, but every time I hear it I feel like ha-la-lu-la!
It solves so many problems on so many levels. Explains why Holdo keeps the plan from everyone. Explains the slow nature of the chase, the First Order wants to board them not destroy them as they have a man on the inside.
Finn’s story would be even stronger. He has a connection to the First Order. Initially he wants to stop the spy. But the spy could be revealed to be a neutral character, just trying to get along in life. Just like Finn was at the beginning, when all he cares about is Rey. Finn can learn from the spy the importance of serving a greater good.
At the end, the Supremancy gets in range to board with cover. The transports come in, and there have the Phasma fight in a place where it makes sense. And you do that all in a limited area, to add tension.
Maybe Rose could be the spy? That would be interesting. Or just some generic guy played be Del Toro.