Legal Question in Credit and Debt Law in North Carolina

I don't know. Admission of documents and videos is governed by the evidentiary rules. Assuming that such evidence is properly authenticated and is admissible and is relevant to whatever issues are to be decided, then yes. You do not explain any relevant details about anything so it is not possible to give you more specific advice.

If $5,000 or less is owed and if your fiance lives in NC, then you can sue your now ex-fiance in small claims. If your ex-fiance does not live in NC you cannot sue in small claims but could sue in the district court if less than $10,000 is owed and if the agreement was made and carried out in NC. If the latter applies, then you will need a lawyer and you and the lawyer can decide what evidence is relevant or not.

If this is small claims, then you will only need the written agreement. I doubt the magistrate would allow you to play a video but you can ask if you made the video and arrange to have equipment at the hearing to play the video. I am not sure why it would be necessary especially if your ex-fiance admits to entering into the agreement.