This is pretty much all bias to me.
You've got some good points on Elma's prominence in the series, but she always headlines alongside Shulk and Rex (aside from in her own game of course). Shulk and Fiora also got a trailer for XC2 since they were part of another DLC pack. Does that mean Fiora has a chance since she headlined alongside the series' pseudo-mascot?
A lot of this reads like conjecture to, such as the devs pushing for her specifically (when they've indicated no previous bias like the ARMS Director Kosuke Yabuki had for Min Min) or her moveset potential (which can be argued for
any character honestly, except Euden), or Rex's Mii Costume disconfirming when another special case like Min Min could hypothetically arise and lead to his inclusion.
If Sakurai is told by Nintendo to advertise Xenoblade
and Monolith Soft suddenly got the funds and resources to port XCX (
which they did not have as of October 2018)
or are working on a sequel to XCX, then I'd say Elma has a chance. I'd say the latter two possibilities are unlikely, however, as Monolith is already incredibly busy with their New IP, Xenoblade Chronicles 3 (if I recall correctly–this could be XCX 2 if it gets a name change, but I doubt it given the tepid reception to the original XCX, which is a valid point), and whatever the hell Nintendo has them working on in addition (BotW 2 likely, maybe something else).
Don't get me wrong, if you want Elma in then I support you wholeheartedly. But don't try to pass off a biased argument as objective fact.