1. What is the "P" position on the ignition lock for? I could not even get the key to go to that position.
That's the steering lock. You have to turn the handlebars all the way to the left to be able to get the key into that position.
That's a pretty standard thing on most modern motorcycles as far as I know.
2. Is there an outside air temperature display in the cluster somwhere?
I have a '13 right now, so I know only that cluster. I don't know of any ambient temperature readout on that cluster, it's much more spare than the one on the '14. I'd suggest using a smartphone with a weather app to get nearby weather conditions.
3.How good is the headlight?
It works. It's very bright.
4. Can the CHAdeMO charger be added later?
Yes, it's technically a dealer-installed feature that can be added later, but if you know you want it, you'll be much better off asking for it to be preinstalled at the factory if you can. The installation process is very involved, occupying a worker's entire day, and many dealers are not familiar with the process. This would be a problem on the East Coast of the US especially where the CHAdeMO infrastructure is not nearly as built-out.