How far will you make it in Firefight?

How far will you make it in Halo 3: ODST Firefight mode.

1 What Weapon Combonation is best for Firefight?
2 What is so special about Red Drones?
3 What is the most important normal target?
4 When should you start being more alert and cautious?
5 What is the best option for getting the Vidmaster "Endure"?
6 What should you do when facing Hunters/Wraiths/Chieftans?
7 What should be your main objective?