I explained on the previous page how I really like the God of Outcasts thing, and yeah, a large part of that is because it is quite a broad thing that does apply to a lot of situations, and can motivate him and act as a moral foundation. I like it a lot better than God of Stories, because God of Stories does not give him much to DO, no personal mission, no goal to chase, or moral foundation, and can only really be used in solo stories. It's more of an outlook or method kind of thing.
But as I said above, I see the Outcasts thing and the Asgardian roles as separate things, Outcasts is personal, it embodies his personal motivation, formed by experiences unique to Loki, but isn't a 'role' in the same way as the Asgardian roles, where there are fixed roles/jobs and different gods need to fill them in some kind of cosmic hierarchy. So I think he can do both at the same time. Like, Thor's always going to be the 'God of Thunder' regardless of what job he's doing in the Asgardian hierarchy, because that is a title he carries due to his personal brand of power, the Asgardian role isn't the 'thunder' bit, (even tho things get a little fuzzy with Mjolnir in that regard, where the enchantment on the hammer means that becoming worthy of the cosmic role also means you tap into Thor's Thunder deal) it's what he does with that power. The same can be said of Loki with the Outcasts thing. As Loki himself said, this has been something that's been a part of him for a long time, kind of informing a lot of what he's done, for good or ill, it's just that he's looked at his past and realized a common motivation for a lot of things he's done, and kind of formalized it with the new title and mission statement, and he's decided to stick up for outcasts other than just himself. He can act on those beliefs and at the same time fulfill the requirements of one of the cosmic hierarchy type roles, since there is potential overlap, but they are also separate.
Basically Role in this sense equals the Asgardian hierarchy thing, the roles are jobs that fate ensures are always filled, so that the universe continues to function and keep it's shape, and they may not have a concrete title associated with them, which means it is sometimes a little hard to refer to them without just referencing the current holder of the role, the 'sword' and the 'sharpening stone' as Loki put it as he was dying, regarding his and Thor's roles, but they tend to become associated with the current holder of the role, which makes things a bit fuzzy, so it's easy to think of the God of Chaos or Sharpening Stone as 'Loki's role' but it isn't necessarily one he specifically has to fill, he's just occupied it for so long that it's become associated with him, the same way Thor's role has become associated with him, and Odin's role with him etc. but these roles can change hands, and have done so before.
the 'God of Outcasts' or 'God of Thunder' is not a 'role' in that sense, it is more like a title representing abilities and/or personal motivations, it may motivate them, or say something about what they do or how they do it, but it isn't technically part of the hierarchy that fate governs.