The Mishna specifies that the reading should be only in Hebrew because it's true, as you said, that it's done in Hebrew. So it has to be on the list.
This is so obvious, as you stated, that this is one of the items on the list that - when discussed in subsequent Mishnayot - where no textual proof is offered that it has to be read in Hebrew.
Moreso, you ...
I’m aware of two terms used in Tanach: either calling her מלכה anyway, as in אסתר המלכה (Esther 5:2-3, 7:1-3, etc.), or the more crass term שגל, “royal consort” (Tehillim 45:10 and Nechemiah 2:6, as interpreted by the conclusion of Rosh Hashanah 4a).