When searching Spindler on the JewishGen databases I suggest using a phonetic or soundex search. Spindler is sometimes spelled Shpindler / Szpindler.
Simon's manifest has his first name spelled Szymon.
There is a WW1 draft card for Sam Spindler in Kansas City that states he served three years in the Russian army. Is this draft card for your Sam Spindler? I wonder if there are extant records from his military service in Russia that may shed light on his father.
Good luck in your search,
Searching: RATOWSKY / CHAIMSON (Ariogala / Ragola, Lith.)
WALTZMAN / WALZMAN (Ustrzyki Dolne / Istryker, Pol.)
LEVY (Tyrawa Woloska, Pol.)
LEFFENFELD / LEFENFELD / FINK, KALTER (Daliowa/ Posada Jasliska, Pol.)
BOJDA / BERGER (Tarnobrzeg, Pol.)
SOKALSKY / SOLON / SOLAN / FINGER(MAN) (Grodek, Bialystok, Pol.)
BOBISH / APPEL (Odessa?)