Harper and Leitch Questions.

Do we have any sources on the history of John Harper and Jessie Leitch before the voyage? I ask because they play a role in the narrative I'm writing. The introduction to Smith, Wilde, and Ismay has been finished and I am advancing to passengers.

If I can't figure out a way around them entering the ship, perhaps I can go with them getting settled in their cabin. If that be the case, what was their cabin number?
As both were in second class, they would have entered by the Aft C-deck gangway.
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Also, it been suggested by his website on John Harper ET Page that:

"...A well known photograph of the second class promenade, in which a young girl is seen holding her father's hand, is believed by many to show young Nina Harper and her father..."

(See pair underlined in Red)