I have been told by more than one LEO to NEVER say anything other than you were in fear for your life. It is their job to try and get the story from you, but if it is obviously self defense, say nothing. In the state of mind one is in after an event like that, it is never a good idea to try and recall the sequence...give yourself time to settle down and think rationally.
I was also advised to empty the chamber in the chest cavity. If you're going to shoot, shoot to kill, otherwise don't bother carrying the weapon.
There is no good answer to carrying across jurisdictions...they may or may not honor the permit. You just take your chances.