Iīm a little bit lost? Is Logan called at least once Wolverine in the past in X-Men: Days Of Future Past? I donīt recall it...
Even though the OT timeline gets erased, when Charles probed Loganīs mind, and saw his future, he could easily get a hold of his codename, either that moment, or any other time, maybe off-screen after he got his powers back.
I donīt really see a need or explanation on why James adopted the name "Logan" in X-Men Origins: Wolverine. Isnīt Logan supposed to be his last name? Maybe he decided to be called by his last name after processing the shock of realizing he is Victorīs brother.
Logan... James Logan... as in Bond