In your first message you stated that Stjepan (Sr) was born 1868, yet census records would indicate the was born c. 1883.

In fact there is a WW I Draft Registration which give info for
Name: Steve Starcevich
County: Kittitas
State: Washington
Birth Date: 21 Jan 1883
Address 10 Penn Ave W, Rosyln
Occupation None, but intends to farm
Wife Antonia at the same address

And then a WW II "old mens" Draft Registration
Name: Steve Starcevich
Birth Date: 21 Jan 1883
Birth Place: Lic, Yugoslavia
Residence: Elk, Washington
listing Virginia MINERICH as the person who always know where he lived

Lic, sounds like leech

You mentioned that Stanislav may have been born out of wedlock, yet the manifest for her and Stanislav indicate she was married and going to her husband Stjepan at Roslyn WI and under the column which asks if she had ever been in the US prior to this 1914 trip there is NO indication that she had ever been in the US.

Checking ship manifests for Steve I notice what appears to be the same man traveling back and forth from Croatia to America.... including this one which appears to be your Steve/Stjepan.... the only issue that both the Ellis Islnd org transcribers and the Ancestry transcribers misread his name! The manifest, which is attched below lists his wife as Antonia at Lic, his destination to a sister at Roslyn and that he had been in the US from 1902 to 1912

Here is what the Ancestry transcribers saw
Name: Steve Stancevic
Arrival Date: 1 May 1913
Birth Date: abt 1883
Birth Location: Hungary
Birth Location Other: své
Age: 30
Gender: Male
Ethnicity/ Nationality: Croatian
Port of Departure: Trieste
Port of Arrival: New York, New York
Ship Name: Martha Washington

And here is what the Ellis Island org transcribers saw
First Name: Stevi
Last Name: Sturcevic
Ethnicity: Hungary, Croatian
Last Place of Residence: Lic, Hungary
Date of Arrival: May 01, 1913
Age at Arrival: 30y Gender: M Marital Status: M
Ship of Travel: Martha Washington
Port of Departure: Trieste
Manifest Line Number: 0013

This was found using Stephen Morse One Step Search using only the first letter of the last name, S, place name Lic, arrival from 1912 to 1914, birthyear 1881 to 1884

There is also a manifest from 1911 from Lic to the US, but the name is crossed out, which indicates this person never made the trip.... maybe he fell in love and married Antonia :)

The manifest is 2 pages with Steve on line 13

Robert