And they were from ashes of Canada 2000 which was from Royal Airlines.
Just to fill in the detail on this one, Air 2000 Canada was an offshoot of Air 2000 UK, a well-established holiday airline in the UK. There were objections to the name and so within a few months, in May 1989, it was rebranded as Canada 3000. The liveries initially looked identical. The UK shareholding was later sold to Canadians and then in January 2001 they bought out Royal Airlines. Probably paying too much for the acquisition they became strapped for cash. Suspending operations on 9/11 was the last straw, Canada 3000 never restarted. The news of the failure was of course lost in the media at the time.
Royal started business in 1993 and was merged into Canada 3000 8 years later.
Crown did indeed have just one DC8-50, from October 1988 to February 1990, when they swapped this for a long-fuselage DC8-61, but they went out of business a month later.
There is a long tradition of Canadian charter airlines having connections in the UK, which continues to this day, as their peak season is in the winter taking the snowbirds down to the caribbean etc. The UK operators in comparison have their peak in the summer. There are thus a number of aircraft leased back and forward between the two locations each season, often the same aircraft being involved for years on end. 9/11 came just at the end of the Canadian low season when they would have cash reserves at minimum.