1. Yes. The only way to end a mission is with a trigger with a type which is one of the ends. End#1, End#2 ... Loose. You need to fire such a trigger to end the mission. The usual way to do this is with a variable:
Somewhere you have
endMission=true
and the trigger
Type: End#1
Condition: endMission
Don't use triggers for camera work, read snYpir's camera tutorial and also messiah's camera.sqs tutorial. You must read them both in that order. It's actually easier than usuing trigger cameras and you get much, much better results.