Do all 2015 Fusion models have a hud?

They don't. You might be confusing the HUD with the two small colour LCDs that surround the speedometer (if the MyFordTouch option is equipped - it's an option on the SE trim and standard on the Titanium trim). The screen to the right of the speedo can be configured to show navigation info (speed limit and next turn) which is what HUDs in other cars are commonly used for. I find this feature to be a really effective "poor man's HUD" :)

Actually, the Fusion Hybrid has had an HUD since 2013, but it's ONLY for the Collision-Warning system. When it activates, besides a loud audible alarm, the in-dash projector flashes a bright red bar on the windshield while the alarm sounds. That's ALL it does, and it does that only if one purchases the package that includes collision warning. But that's why dc3355 has been hearing about the Fusions "HUD." It's an HUD only in the technical sense.

Thats correct my 2017 Fusion Platinum has the HUD and it works as a collision warning system. Have seen it only once so far.

It also lights up when starting the car