The snow clearing special was also a passenger special with a consist of a single coach, and, assuming the same consist was used as the day before, there was also an open rider gon and a caboose. I don't know who was aboard the day of the derailment, however the day previous I rode a Friends sponsored special and there were indeed several english speaking people with decidedly non-American accents aboard.
I doubt that anyone has any photos of the derailment as it happened given the location. The problem is that it occurred out of sight from hwy 17, at a snowbound crossing so there probably wouldn't have been any bystander type photographers present. Also since it occurred on a more or less straight stretch of track there probably arent any photos (or video) taken from the train itself. As far as photos taken immediately after, Doris and Jim Granflaten were aboard and sent five photos of the derailment, (well, the aftermath), which were posted on the Friends news page (search for "derail" and the entire available date range).
Given that there were only three passenger related cars in the consist, it is unlikely that the additon of a second engine was caused by the presence of the passenger coaches.
As for cost, the $150,000 mentioned above sounds about right, and would have been the responsibility of the operator (at the time Bartholomew).
Hope that helps
Don