They were on the Wilson Line's Hero to England and then on an Inman Line ship from England to NYC.
Translate shipping lines of 140 years ago with airlines of today: it's POSSIBLE to change your ticket/destination but it will cost you - on the other hand the airline/shipping line may shift you to another flight/ship (with a different destination) because for some reason, usually technical, the original flight/ship can't depart.
Now, Norway to England would normally have taken some two days. England to NYC would normally have taken some eight to ten days. If there had been some misadventure such as the one you describe it must have been in all the papers, at least all papers in New York. I'm quite sure there are newspaper collections that will give you lots of details.