@Gishe
It may be the mangaka or it might be the Japanese language in general. A search of "regista" and "football" in Japanese yields 672,000 results so the term is used often enough.
https://www.google.com/search?sxsrf...m9-gS2y77oBA&q="レジスタ"+"サッカー"&oq="レジスタ"+"サッカー"
Whether their usage of the term is similar in nuance to other languages is also questionable. There are two things that can truly resolve this.
1. We get a Japanese person who's a football fan who can tell us about how these terms are used in their language.
2. I can spend time reading up about Japanese football terminology on sites like https://activel.jp/articles/B5jqq
in Japanese instead of translating more of the manga. I think we can all agree that I should spend my time on the thing that matters more.
The other members of the staff were the ones insistent about having a terminology page despite the tricky nature of these terms.
My stance on this was let the readers google and learn about it themselves.
Now that I've given my standpoint on this, I'm not going to address anything that pertains to positions again.
I'll let the staff members who insisted on a terminology page and people who take an issue with said terminology page settle things themselves.