1. The question is in English not Yiddish.
2. If it is every day there might be a problem of becoming too friendly. of course, you can start include another woman. Then they will talk to each other the whole time.
3. Where is the halacha that men and women must address each other by their last names found (see Taanit 20b that Rav Ada bar Ahava ascribed his long life to not addressing people by their last names)? What did Jews do before the authorities required them to take last names? Did they say “Mrs. Golda” (cf. Rav Ovadia) or perhaps like the English “Mrs. Yossi”?