1- We know that they made Storm's hair "grey" in X2 and X3. How do you explain that, in-universe?

2- Have you noticed that Beast had white streaks in his hair, in "The Final Stand"? Did he sport those at the very end of DOFP too?
Wondering if that means that we're supposed to (retroactively) think that his aging process has become "normal".

3- Have you noticed that, from ORIGINS onward (even the following X-Men movies: "The Wolverine", "Days"), they left Hugh Jackman's forehead totally uncovered by hair? Do you think that it looks bad in comparison with the Wolverine haircut of the original trilogy, where the forehead seemed more "covered"?

Thank you for your feedback or answers.