The following is the marriage of Eva and possibly the marriage of her sister Maria.
New York City bride and groom index
Eva Rasenen and William Nelson, married May 14 1917, Manhattan, certificate # 15345
Mary Rasenen and Albert Hausen, married Sep 5 1919, Manhattan, certificate # 29841
If you "Google" the name William P. Gagner you will find his present address, it appears that he is among the living. He may be able to answer your other questions.