I gave the daf yomi shiur (Bava Metzia 81) yesterday, so here are a few thoughts.
Just googled around a bit. Found this https://he.wikipedia.org/wiki/%D7%99%D7%A2%D7%A7%D7%91_%D7%94%D7%9B%D7%94%D7%9F_%D7%9E%D7%A0%D7%94%D7%A8_%D7%A4%D7%A7%D7%95%D7%93 . I don't see how it could mean river.
Agreed. Similarly, one of the Rav Kahanas was Rav Kahana of Nehar Pekod.
Just googled around a bit. Found this https://he.wikipedia.org/wiki/%D7%99%D7%A2%D7%A7%D7%91_%D7%94%D7%9B%D7%94%D7%9F_%D7%9E%D7%A0%D7%94%D7%A8_%D7%A4%D7%A7%D7%95%D7%93 . I don't see how it could mean river.
Agreed. Similarly, one of the Rav Kahanas was Rav Kahana of Nehar Pekod.