It just dawned on me that Timber Wolf uses Vixen's Tantu Totem as his Legion sysmbol.

If you think about it, their powers are very similar. Could Vixen be Timber Wolf's ancestor? Maybe Timber Wolf has subconscious pull towards to use the Tantu Totem.

No. I think any similarity between their symbol is coincidence. Timber Wolf is an alien whereas Vixen is human.

Timber Wolf is actually human. Well, from what I remember from his original story.

No.

Timber Wolf is actually from the planet Zoon (or Zuun, depending on which version of the Legion you're referring to). Now, that's not to say that somewhere in the thousand years between Mari McCabe's birth sometime in the 20th century and Brin Londo's in the 30th, that humans don't find their way from our little blue marble to the planet of TW's birth.

However, such potential history lies in an empty spot in the records of the 30th century, so no proof of such a diaspora has ever been suggested in the Legion books, to my knowledge.

When Vixen was created in the early 70s, the artist may have had Brin's insignia unintentionally in the back of his mind, but there has never been any actual admission of any connection between the two characters to my knowledge.

So, I'll agree with the previous respondent who says the similarity is merely coincidence.