Kroll Family Research

I have been helping my daughter research her boyfriend's family tree. His names include Kroll,
Rosetti and many others. It is opening up a new area for me to research because at least his paternal family are Jews. As far as I have discovered so far I have no Jewish ancestry in my own line so now I have to learn a whole new set of resources to learn how to use. Would love to learn from some of those with experience in using records specific to Jewish research.

So far what I know is his grandfather was Morton (aka Max or Mac) Kroll born 14 September 1918 in Ohio (presumably Cleveland) to Jack Kroll and Mollie Evans. Mac (as he was known to his family) had a younger brother Sanford (aka Samford and Sandy) born 22 March 1928. At some point Jack, Mollie, Mac and Sandy all moved to the Los Angeles area of California. Mac died 22 January 1978 in LA County, Sandy died 11 October 2000 in LA County, Jack died 13 June 1963 in Orange County, Mollie  died 03 June 1957 in LA County.

On ancestry.com I found US, Ohio, Cuyahoga County, Jewish Marriage Record Extracts, 1837-1934 that showed Jack Kroll married Mollie Kroll July 4, 1925, but it also showed both had been married previously and both divorced 8-26-1924 in Common Pleas Court. Marriage performed by I Kresilov.
It looks like they were married to each other, divorced and remarried from what I am understanding from the records.

From those records I found out Jack's parents were Abraham Kroll and Vera (no maiden name listed), and that Mollie's parents were Morris Evans and Sophie Skalnik.
Jack's World War I Draft Registration Card 1917-1918 shows that on 12 September 1918 he was married to Mollie Kroll. It also shows that he was born 1 May 1899 in Russia, which is consistant with the other records I have found so far.

Both the 1920 census and 1930 census have Jack and Mollie married and living in Cleveland, Cuyahoga, Ohio.

Census records show that Mollie was born in New York, using that information I found a likely match on the 1900 census in Manhattan, and then the same family group in 1910 in Cleveland, Ohio.
If you are related somehow or have ideas on how to further my research on the family please feel free to contact me.