Radio transmissions from Comanche N9456P at 1:15 in the video clip above. He makes an odd remark about a training lesson when the tower asks if he's experiencing any difficulty.
NTSB onsite briefing here:
Facebook videos allegedly of the pax boarding to NSFW 'urban ethnic' music in this article:
Watch Video of Scottsdale Victims Minutes Before Fatal Plane Crash | Phoenix New Times
Not sure I can see six people onboard even if the plane has the kiddie seats in the back. It has been suggested that the plane would have aft CG and gross weight issues if loaded with full tanks and six adults.
Possibly there will be further video evidence recovered from the burnt cellphones. I'm sure some of the pax were doing selfies during the takeoff.