The Wicked Bible really does exist. It was published in 1631 by Robert Barker and Martin Lucas and, as mentioned in the film, Exodus 20:14 reads "Thou shalt commit adultery".
In Stanley Tucci's first scene in the movie, the location was mentioned as "Vatican City" with a drone shot. They were actually walking next to King William Court in Greenwich, London. You can clearly see the chapel of St Peter and St Paul.
Stanley Tucci and John Krasinski are brothers-in-law. Stanley Tucci being married to Felicity Blunt (2012) and John Krasinski being married to Emily Blunt (2010).
The Lusitania is relatively accessible to divers, having sunk just 18 miles off the Irish coast. Several dive operators offer expeditions to explore the extensive debris field. However, the ship is not intact, as the British Navy dropped depth charges on the wreck during World War II to prevent German U-boats from using it as cover. It's worth noting that the Lusitania was not sunk by a Nazi U-boat, as the Nazi regime did not exist in 1915. The attack was carried out by a U-boat of the Imperial German Navy.
The Purdues father is named Harrison, an obvious nod to Harrison Ford who starred as Indiana Jones, one of the original treasure hunter movie stars of which the movie drew inspiration from.