Ultros was again, just a reference to FFVI and not a direct link to FFVI's world (he was not the FFVI Ultros at all, as it was clearly stated he was actually a failed creation of the THM's Guild, who then abandoned him because he was considered a failure, which makes one wonder exactly what it was they were trying to make).

Typhon on the other hand.... who knows exactly where he came from - his origins were never explained. But I guess he can just easily be handwaved away as another 'Voidsent'.