OEL is an oxymoron
Marvel have decided to produce an X-Men manga. None of the people associated with it are Japanese. Now I think Raina Telgemeier is a very talented writer, and may well produce an excellent comic, but it still won't be japanese, and it probably won't read much like a comic produced by Japanese creators for a Japanese audience, so calling it "manga" seems a bit of a cheat to me.
Original English Language manga is to me a contradiction in terms. If it's created by English speaking people for an English speaking audience in a western style for a western publishing format, then it doesn't matter how big the eyes are or how many speedlines you include, it's not manga. It's no more manga than strawberry flavoured candy is in any way related to actual strawberries. It might be very nice strawberry flavoured candy, but it can only compare favourably with other strawberry flavour candy. When compared with actual strawberries, you cannot help but notice that it is not a fruit.
It's cultural appropriation at its worst. Japanese culture tells stories in a different way, with different emphasis and pacing, and with different references. Attitudes to the medium of comics are different in Japan, which leads to a different publishing structure. It's not just difficult for an American production to properly emulate a Japanese comic, it's almost impossible. And most of the time, they don't even try. They simply pick up a few superficial stylistic tips, and think that's enough to hitch a ride on the manga bandwagon.
And one other thing: if you are a westerner, creating a comic to be published in America to be read by Americans, constructing it so it reads right to left is a ludicrous affectation and I will mock your foolishness and cast aspersions on your character.
You have been warned.