Should I even bother...
... I guess I should...
Number 3 I think: No be curious... and well armed... you might just capture an Alien ship and be able to use it to launch a counter attack on them. If you are really lucky you might even be able to reverse engineer them and build a fleet of them. examples: Space: Above and Beyond, Stargate SG-1, Independence Day.
Number 5: Newt Died, oh and innocence didn't help her brother now did it?