Simple Answer: Hats will only be on the characters whom wore them in the original (Oddjob, Ouromov, etc), and will be on the model when you spawn already. There will be no option to remove them.
The reason we didn't have hats in the first place is, we weren't able to shoot the hats off, like the video shows how you can [now]. It would of looked bad before when someone died and the had stayed put.
However, like we have said. Don't get your hopes up that this feature will be in Beta 3. We have other things that are more important than, the ability to shoot someones hat off, or to have the hat apart of the model.