People being murdered. Plot twist: the murdered people were all actors

Movies
1

Hey guys, would really appreciate some help with finding this movie:

I remember a person going on a cruise (??) and people being murdered on the ship. In the end it turns out that everybody except the main character were all actors.

I watched this a few years ago and not entirely sure if it was even a cruise but I feel like I remember somebody dying in a freezer and somebody “dying” on a chair bounded.

2

It is not on a cruise, but maybe?:

3

Could it possibly be April Fool’s Day 1986? They do go by ferry boat and there is some death to an island home and people start getting killed. The ending discloses the overall plot you mention.

4

Possibly also - (but I haven’t seen this one to confirm came up in my search)