@lividus
A mangaka gets 10-15% royalty per tank sold by the original publisher in Japan, in this case Kadokawa. However, licensing deals are different in that they are usually based on a guaranteed licensing fee based on number of physical copies to be printed by the licensee (in this case Yen Press) + 7-8% bonus for every book sold beyond the original deal. An author gets a cut of 1-3% of each "bonus" book because that's guaranteed under international licensing norms, but if the original work was created under a for-hire contract (which almost all mangaka are bound into) then the cut from the guaranteed licensing fee is unclear. Now, traditionally digital copies of a book are counted under the "beyond original deal" numbers because, well, they're not physical. However, for Yen Press whose main business is digital I'm not sure they would structure their deal this way.
If the deal was structured the traditional way Mori-sensei would get 1-3% of the USD 10.48 minus tax selling price of each Otoyomegatari digital volume, but only about 10-15% of the guaranteed licensing fee for physical books. If Yen Press includes their digital copies in the base licensing fee, and assuming the fee is based on the 7-8% rate as well, then Mori-sensei would be getting 10-15% of the 7-8% licensing fee for each copy, physical and digital, sold by Yen Press.
This is basically why mangaka don't usually make a fuss about scanlations. They don't really get anything from foreign licensing of their work.
Edit: Wait, this post doesn't sound right. Where the mangaka benefits from the official foreign publication of their work is in their level of favorability in the eyes of the original Japanese publisher. Foreign licensing deals are very lucrative to the publisher even if not directly to the mangaka, so good foreign sales tells the Japanese publisher that the mangaka has special value beyond the Japanese market. This gives the mangaka better favor when negotiating terms with the publisher and can even get them special treatment. Mori-sensei gets free "research" trips abroad and even a special deal to publish promotion manga from a marketing association for the 'stans. So even if the direct financial benefits are minimal, good sales of the official English version of the manga helps the mangaka greatly. Go swarm Bookwalker now guys! It's KADOKAWA's own digital bookstore, so good sales of Otoyomegatari there gets reported back directly to Mori-sensei's corporate overlords.