Long hair as well as braids are confirmed, judging by what was presented to us earlier. Check out the Character Creation live stream from about a year ago. Hair physics will likely also exist for movement, but I'd say wishful thinking for storms/winds and such. Microclimate modelling would ostensibly be required to achieve that and honestly, they've got their hands full as it is.
Oh since hair is being discussed here I was wondering will there be a hair physics that allows hair to grow over time? Has this been something that was mentioned before in developer previews?
Balding has been mentioned in the design journals as part of the aging process, but I don't recall anything about hair growth. Seems like it would exist except that that means hair maintenance would be required, which is a bit too much realism for a game IMO.
23 MAR 18 V-SbS
Once you get in game it is theoretically possible for you to set your hairstyle to whatever you want. So we don't at this point have male hair and female hair. It's just hair. It is also important to note that not all tribes will necessarily have the same amount of facial hair or hair that grows as quickly.