Well technically Noxus is invading on several fronts if we count LoR and other lore media, such as: Ionia, Demacia, Freljord, Shurima, and is currently infiltrating Piltover and Zaun.
Suspicious lack of Arcane Viktor X)
One is an active force in saving and healing people in the world....and then there is Kayle, which for centuries has completely detached herself from mortal issues and wants to become as close to celestial values she assumes her mother embodies.
To be honest, Mercy has more in common with Soraka than with Kayle, even though visually yes the two do look very angelic.
You have to ask the fortnite wiki community about that for a more accurate answer. From what Ive seen and assumed, the skins have a very narrow window available for purchase. Even Arcane Jinx sale lasted less than a week before it was removed from store. It is possible that the skins may return at some point (possibly for Arcane Season 2), or in some other event. Fortnite cosmetic store is a confusing thing with many problematic mechanics and now it is structured (in LoL at least you have the option to see all currently available cosmetics at once).
Since Arcane does not adhere to Main canon, they can honestly do whatever they want. Obviously Warwick seems like a logical step, along with Orianna. Blitzcrank would be nice to see being made.
I wouldnt use Necrits old videos for power scale examples since they quickly go out of date as new lore gets introduced. Sharjo keeps a more up to date tier lists for these things.
Most Fav (Lore):
1. Viktor
2. Jayce
3. Pantheon
4. Heimerdinger
5. Aurelion Sol
Least Fav (Lore):
1. Seraphine
2. Qiyana
3. Cho Gath
4. Shaco
5. Kog Maw
Depends on your playstyle. Jinx, Ahri, Seraphine are ranged champions while Garen and Yi are close combat champions. They are all fairly easy to learn. Although all the ranged ones have some additional skillshot ability learning curve while the close combat ones you need to learn when to attack and how to attack ranged champions with them.
Watch "Love, Death & Robots", "Hilda", "Monkie Kid", and any movie done by Cartoon Saloon.