I do have to agree with some of the fans that Hela seems like the best wife candidate without a doubt. Incest, or not. They're not even full siblings either.
I think Baldur should age slower than any asgard. It has the healing factor given by Solheim, the healing factor of Apocalypse, its vitality is much stronger than the other Asgard.
Thus, when the avengers canon begins, Baldur must look younger than Thor.
It will be very funny when Odin dies. Thor and Loki will wait for a fearsome warrior to appear as described by their father, but a goat will come out instead, after all the anticipation.
Dayside