possibility Nr.272 in list: http://www.ellisisland.org/search/matchMore.asp?order_num=19...
possible this would be the brother-in-law (my guess). he went to his friend Franz Jost! who was also from Rabafüzes. i must look again if can find out on shipmanifest if Cecilia came with Johann´s wife, which was then her sister. so possible both came in same year after him in June and Franz was of sure a relative i think, maybe their brother or cousin.....now, it looks like she traveled with others from Rabafüzes, as right side of shiplist shows, but it´s a pity left side where are the persons listed is no name only the line-number. but the line nr. 15 shows that a person from Rabafüzes went to friend Anna Jost, Atiles? (Allentown meant?) PA, Lehigh County like all others.
http://en.wikipedia.org/wiki/Lehigh_County,_Pennsylvania
http://maps.google.at/maps?hl=de&q=Lehigh%20County&u...
would this all fit?

First Name: Johan
Last Name: Koppel
Ethnicity: Hungarian
Last Place of Residence: Rafulyes, Hungary
Date of Arrival: Feb 13, 1909
Age at Arrival: 34y Gender: M Marital Status: M
Ship of Travel: La Provence
Port of Departure: Havre
Manifest Line Number: 0010

there was also a Cecilia Jost which went to brother Josef Jost in Macungie PA in Jan.1910
http://maps.google.at/maps?hl=de&q=Lehigh%20County&u...
http://www.ellisisland.org/search/matchMore.asp?MID=16900218...
First Name: Cacilia
Last Name: Jost
Ethnicity: Hungary German
Last Place of Residence: Raabfuzes, Hungary
Date of Arrival: Jan 19, 1910
Age at Arrival: 25y Gender: F Marital Status: M
Ship of Travel: Blucher
Port of Departure: Hamburg
Manifest Line Number: 0005

1905 also a Cecilia Jost came from Raabfidisch/Rabafüzes, went to brother-in-law Frank Urban:
First Name: Cacilia
Last Name: Jost
Ethnicity: Hungarian
Last Place of Residence: Fedisch
Date of Arrival: Jan 27, 1903
Age at Arrival: 19y Gender: F Marital Status: S
Ship of Travel: Kroonland
Port of Departure: Antwerp
Manifest Line Number: 0015

arrivings for Franz Jost with some of Inzenhof and Rabafüzes/Raabfidisch.not easy to make out the friend of John Koppel:
http://www.ellisisland.org/search/matchMore.asp?MID=16900218...

the Jost showing a never "ending story" for arriving in N.Y.
there immigrated really a "clan" of Jost that time from Rabafüzes and Inzenhof. too much to show all here. best you search more for yourself at www.ellisisland.org ......