Many of the Latter-day Saints who still believe what the prophets have taught about the New York Cumorah also find it significant that the Lord named the site to be built across the Mississippi River from Nauvoo.
Let them build up a city unto my name upon the land opposite the city of Nauvoo, and let the name of Zarahemla be named upon it. (Doctrine and Covenants 125:3)
Because the Lord instructed Joseph Smith to call the site across from Nauvoo by "the name of Zarahemla," it's logical to assume that site was first possessed by Zarahemla.
The scriptures don't tell us much about Zarahemla, either as a person or as a title. When Mosiah and his people left the land of Nephi, they "they discovered a people, who were called the people of Zarahemla. Now, there was great rejoicing among the people of Zarahemla; and also Zarahemla did rejoice exceedingly, because the Lord had sent the people of Mosiah with the plates of brass which contained the record of the Jews." (Omni 1:14)
But all in all, the Iowa Zarahemla fits well with the New York Cumorah.