Hello Boris,
-The photo of the guy on the rock next to the two main photographers
This photo is actually set in the Vertex admin area under the "theme specific" options. You'll see a URL to it there.
-I want to remove 'maternity' in the row of most recent photoshoots'
The S5 Masonry module pulls in the categories so just open that module up and remove the "maternity" category from being pulled in.