If I have 6 points and conquer one battlefield with Flanking, then use the same unit to conquer the other battlefield (via cards like Last Breath), do I win the game, or do I need different units on both battlefields?

Ruling: You will win the game as you've scored on all battlefields that turn.

Nuances:

• The same unit can be used to conquer both battlefields in the same turn (e.g., via Last Breath)
• You don't need different units on each battlefield to win