When victory conditions are checked?
1/ at the end of an action/reaction cycle
2/ at the end of a player turn
3/ at the end of a game turn
4/ anything else
Scenarios have a fixed turns number. what happens if at the end of the indicated turns no side have achieved his victory conditions? is it a draw.
If a draw is possible how do you handle it during campaign games?
Each scenario describes exactly what happens in every question that you've asked above. It is not the same for each one. There is no single answer.