Those were introduced after TLJ, and TLJ has much more of a Norse Pagan feel to it
I had the same feeling. Northlands and April's part of the story certainly are influenced by Norse mythology. April's clothes in the second game look a lot like the ones vikings wore, her funeral is organized in the same way they sent their heroes to the afterlife, her fighting against Azadi with their monotheism reminds of vikings fighting against Chritianization, the symbol of Balance slightly resembles the tree of life symbol... Then Etta comes from Midgard which is a pretty obvious reference. (By the way, anyone else considered it may be the two worlds combined before or after the Divide?) Also, Lettoch is mentioned which is in Scotland, so Northlands again. And the Yaga is somewhat similar to the three main Norns. Also about Saga, someone mentioned it earlier, but it may also fit well in your theory: https://en.wikipedia...and_Sökkvabekkr
So while I'm not sure that's how things were meant to be in the game, I like your theory a lot, because it works well (combined with what you've written in other threads) and it suits my perception of the story to some extent.
By the way, you've mentioned in other thread that Azadi Goddess might be the White Kin, and I do agree with it.
1. The Goddess is definitely a female, which rules out Lux, because Lux is genderless (unless of course at the beginning of times Lux was one with Zoe and the Goddess is Zoe)
2. The sisters have something like image of a dragon on their belts (can be seen here: https://youtu.be/rO5...dbM?t=1h56m59s at 1:56:59, also just noticed that Vamon has some runes on his clothes, which is so strange, because where're Azadi and where're the runes..)
3. In their religion The First Mountain is mentioned which may be the Mount Tireney (or, if the Goddess is Lux may be it's the cloud peak)
4. Kian's mother mentioned Amah in his dream, which means mother in several languages, and the White Dragon IS mother.
Of course may be their Goddess is just some abstract deity and has no relation to any characters.