Ahhh, lost track of this in the Great LJ Outage...

1. River knows some... special settings on the sonic screwdriver.
2. River, without a doubt. The Doctor is a bit envious and quite wants hair like that next time.
3. How much messing about with time is allowable.
4. Well, the Doctor is used to that sort of thing but it's not as though he has the healthiest coping strategies... maybe River.
5. An eternity of chasing one another around time and space, having laughs.