Have you contacted the cemetery?Altho no dates on tombstones, they may have additional info.
Here's a bit of info.... 2-2-1899 Union Grove, Harrison Co IA John Hiram COOK s/o Wm and Susan COOK m Daisy D BABB age 16 d/o George Francis BABB/Alice SEARCY [Daisy b 10-3-1882 Harrison Co IA] WWI Draft Reg, Omaha; John Hiram b 9-15-1877; streetcar motorman; 6'2" slender/br eyes/blk hair; missing tip of finger on right hand/no teeth; wife Anna Belle. He d 1920-30; unless Annie moved elsewhere she d 1930-40.
1900 Glenwood, Mills Co IA NICOLS James P 37 KY KY KY Anna 27 KY KY KY Walter 6 IA [WWI Draft Omaha; b 9-10-1894 Glenwood IA, single, car checker/usher for Union Pacific RR; tall/slender/ bluee yes/br hair}
12-26-1889 James Pryor NICHOLS m. Annie B MURPHY, MIlls Co IA had son b 5-29-1891, who apparently didn't survive.
Obit for James P NICHOLS in the Tribune 11-7-1906 available from the Glenwood Public Library