To be honest I guess you should call off the contest. It is not possible to fairly choose a winner with this amount of manipulation in the back. I apologize if I did anything wrong by sharing my entry on facebook. I am not sure anymore if that could be seen as unfair too even so I mentioned to watch the other videos, but as others stated already, having way more likes as views is slightly more problematic than maybe 5 biased votes because of ones popularity.
Even so I appreciate the thought of you to enable as many people as possible to enter the contest I guess it was not the best idea to choose a topic with such a wide range of interpretation. Simply because it doesn't help with the establishment of a reasonable way of voting either.
Personally I have to say I really had fun creating an animation for your contest and the money was and is irrelevant to me. I was simply happy to have another reason to create something. I guess a lot of participants share that thought. Nonetheless I would hate to see somebody win the prize that had some dishonest methods used to get it.
As for the suggestion of a jury, I really think the most unbiased jury would be you to be honest. There is no such thing as complete objectivity and I figure regardless of your personal relationship to the participants you would probably be the best fit since I trust you to put at least some reflection to your votes.