I don't think Tav/Durge really exists, how could they even be told canonically in further parts?
In DA there were always fixed heroes, the origins were also fixed, one gender, one race, class there are only 3, so it wasn't that difficult, in DAO we could choose from 2 genders and up to 2 races (mage origin), but BioWare clearly stated who was canonical. All DAO origins were canon, but only one managed to become a Warden, DAI was the same and DA2 only had one hero and both genders were canon according to BioWare.
I don't see that in BG3, except for the companions.
You can always choose from two genders in DA and only DA2 fixes your hero as being human. There are three races, four in DAI.
And BioWare sadly has a history of mak heros canon,which people tend to ignore of course, because it is stupid.
As for the topic: it seems, the origins should just be normal companions, according to the numbers, over 90 % of player make a custom character anyway.
