1. The woman in red is dressed very differently than other passengers, she dances quite differently than other passengers and looks quite different ethnically (Mediterranean in the broadest sense of that word from North Africa, Levant etc.) she is dancing very close to Amy and what caught my eye is something 'unnatural' in her demeanour.
2. The elevator sequence: I am not as sure as others that Amy is ok at this point of the video. She seems to crash into the non-button side of the elevator (?) gropes to press it several times (?) stumbles (?) Tough to see though. If so there could have been an earlier attempt to drug her and she didn't drink enough or as an athlete she was too strong.
3. Find Amy I assume you think the reason the abduction was so late is that they were waiting till they were close to the port? If they wanted her so badly though it seems a bit dangerous to wait until this point.
4. The sightings in the Caribbean are very strange it would be much 'safer' to take her to South America proper not the holiday parts. IMO if she spent considerable time in the Caribbean it is VERY likely there is local knowledge of this.
5. I am wondering if local authorities in Curacao have not been alienated by the attitude of North Americans. I don't think Curacao has more of a role in human trafficking than many European countries or the US or Canada. If she was really in the Caribbean for months or years I think a gentler more truly local approach would work much better than the confrontational approach that law enforcement is corrupt there etc. (and yet that we shouldn't broach that of US authorities, as a possibility).
I will go out on a limb and say that if Amy is alive this has been the biggest obstacle to solving the case. You would need to recruit Caribbean people to do the spying and hear the gossip any DEA type approach simply will not work though people will appear to cooperate with you. But you will get nothing.
6. As for Mr. Z that is a very uncommon name it doesn't appear at all in Canada 411 though there does seem to be at least one family with that name around Toronto.
7. If Y is really hours away from helping to kidnap Amy during the dancing why "wine" with her he is the only one doing so - why recklessly draw attention to himself? Why dance with her at all? Possibility that Y may be absolutely innocent after all he didn't fail the lie detector test and I assume he agreed to take it BUT yes may know something.
8. I would try to find out something about the woman in red and her friend though I realize it may be impossible at this point.