The king - In marginal reference. Nahash, king, etc. The interval between the two events, not less than 50 years, and possibly more, is against his being the same as the Nahash of 1Sa 11:1-15.
The Ammonites are almost always spoken of as the children of Ammon, from the name of their first ancestor Ben-ammi Gen 19:38.
Hanun - The equivalent of the Carthaginian Hanno, from the same root as the Hebrew, Hananiah, Johanan, Hannah, etc. The same name appears in composition with Baal in Baal-Hanan, an Aramean king Gen 36:38-39.