No HDMI or CANBUS port but most of us Inspire guys don't use the HDMI port, and nothing uses the CANBUS port right now anyway.
It'll be 720p to the app like the Inspire. Somebody picked apart the latest DJI Pilot app update on the Inspire forum and found images of the Phantom 3 clearly marked as such, to display during compass calibration etc, so it'll be the same app for sure.
The larger controller port is definitely USB to the app/device, again like the Inspire remote.
I'll venture a guess they'll not offer a 2nd controller option for the camera operator on the Phantom line.
But man, this really degrades the value of the Inspire. Hopefully they'll offer an MFT 4K camera upgrade option for the Inspire to help us I1 folks feel better