This post also says that #REMOW also has #KatekyoHitmanReborn. Does this mean that #DiscotekMedia has to answer to them regarding that #anime's distribution?
https://mastodon.social/@theoasg/114479398209974203

Side note: REMOW lists Shueisha as their "major shareholder".

Do they mean that as in "Owning more than 50% of the company" or do they mean "The corporation that has the largest percentage of our shares, even if it's 50% or below"? (Think "Sony owning ~10% of Kadokawa" for the latter)

I'm guessing it's the latter, because of the "principal shareholder" language used in the press release linked below and the lack of actual share percentage numbers mentioned.
https://www.remow.com/en/news/285/
REMOW株式会社|NEWS

REMOW Co., Ltd. is engaged in global content sales, the development of streaming services, and production with the goal of bringing Japanese entertainment to people around the world.

REMOW Co., Ltd.
On top of all that, I doubt that just one out of this list of companies owns more than 50% of REMOW.
https://www.remow.com/en/company/
REMOW Co., Ltd.|COMPANY

REMOW Co., Ltd. is engaged in global content sales, the development of streaming services, and production with the goal of bringing Japanese entertainment to people around the world.

REMOW Co., Ltd.