There has been a lot of misinformation spreading around, and I can't blame you really, for we have been starved of information.
I like to think I am one of you (I know, I know) and where I am from you share with the people who are like you. So I will share what I, myself, have found out through nepotism.

The legendaries are not two wolves, but one. One wolf that, depending on which game you got, will change form when holding a special mythical item.
The wolf Pokémon's name is Marroknight.
In Sword, the mythical item is a sword (duh) based on Excalibur.
In Shield, the mythical item is a shield based on Pridwen.

Apparently the direct refers to the legendary wolf "serving" the player.

That is all I know for now.