I found the Ellis island manifest for the younger John and family, recorded as arrived 12/11/1906, Johann Rubgalwis, 25, with wife Else 22, August 1y6m, Ott 6m, as well as John's sister Martha 19, all from Neustadt, going to brother in law Johann ?, again can not read the last name, but the address is the same as the elder John's arrival, 8927 S. Michigan Ave, Chicago. This is one of the misfiled manifests, but can be located using the Steve Morse web site at Series T715, Roll 809, frame 359.
On family search labs web site, I found a record of birth for Alma Kanshat, born 10/25/1910 in chicago, to father Richard Kanshat, and mother Martha Rupkalvis. I think it likely this is the same Martha who arrived with brother John in 1906. However, I could not find this family on any census.