Not much is known about the Schwartz couple, other than that they were in their 80's, they were first class passengers, and both committed suicide through means of overdosing on cyanide.
It is also rumored by the fandom that Mrs. Schwartz is known as Coffee Filter Lady. This rumor is hard to confirm as she is seen after her death was spoken about. The name "Coffee Filter Lady" is derived from the outfit that the possible Mrs. Schwartz actress is seen wearing.
In season two when we find out they committed suicide, their quarters were given to Zarah Ferami and Andre Layton to use as a headquarters and because Zarah was pregnant.