Yes, I keep bumping up against the Chicago Ewerts when searching for the Cleveland Ewerts. I have no idea if there's any connection, though, perhaps from farther back in history.
Someone on one of these boards recommended that I look into a Mennonite connection. Apparently, Mennonites came from the Prussia/Poland/Russia area to Canada then down into the USA. With the proximity of Chicago to Canadian immigrant routes, perhaps this could apply to your folks? The information is found in a online database called GRANDMA. There are several websites devoted to Mennonite immigrants and there are quite a few EWERTs among them.
So far, I don't know my G2GPs. So far as I know, when my EWERTs came from Congress Poland to Cleveland in the 1890s (Russian Empire at the time), they were Lutherans.