I forgot to include the following in Srarah Part 4.
The Ramban Shemos 6:23 discusses why certain people's wives (and the wife's fathers) were mentioned when discussing the lineage of Moshe & Aharon. He says "al derech hapshat" that the mothers of kings are frequently mentioned, and he mentions Divrei Hayamim II Ch 20 and Melachim I 15 (even though in Nach, the meforshim explain she was mentioned because of how evil she was, not exactly high praise). Perhaps the Ramban is trying to say like Tosfos (the basic answer) that a melech must have his mother from Yisrael also, not just the father. This is debatable, but it's a possibility.