There is an issue with traits which effect hearthling appearance, where the appearance changes do not get applied correctly when the hearthlings are created in the embark/new game screen.
Currently there is only one trait in the base game that does this and I believe this is why the magnificent beard trait is the only trait in the base game that cannot be obtained when embarking, only from new hearthlings joining the town. This will also effect any trait added by mods which effects appearance (shameless plug)
My hypothesis is that when a hearthling is created, its appearance is first randomized and then it’s traits are applied. However, when hearthlings are randomized in the embark window (but interestingly, now when they are first created even in the embark window) their traits are randomized and then their appearance is randomized. This has the effect of undoing any appearance changes made by traits.
If this does not get fixed, then if anyone finds a work around to this I would be very excited. Perhaps by having a handler that triggers when appearance is modified, which can immediately set it back? (although this could cause an infinite loop if two traits both affect the same element…)