It's cop-101 to confront people assertively when you think they are lying. The dog alerted, the officer felt that there may be drugs, so he aggressively questioned your daughter. Many times that's sufficient to get someone to admit that there are drugs there (if there are). if not, then they will hold out as your daughter did. But, when faced with the speech, "Tell me the truth now and it'll go better on you, but if I search there and if I find drugs, you're going to jail for <additional charges>," ... many people fold if they are holding.
Police work is not retail work, and doing our job means sometimes being a prick. Often, it can be rude and even ugly. Unfortunately, sometimes good people get wrapped up in the "bad cop, bad cop" game. I still don't see a violation of any kind except for MAYBE rudeness ... and even that's dependent upon the circumstances as they presented themselves to the officer at the time.
And even a review of the video will not tell the whole tale. Video does not capture everything - either visually, or certainly not by the other senses. Ultimately, I think this is a non-starter from a legal perspective. But, it's your time and money at stake to pursue and if it gives you some more peace of mind, go for it. But, keep in mind that you may not agree with the reasoning for the search or the attitude even if it might be perfectly lawful. As I said, the real job is not pretty - criminals don't just walk up and confess and flash us with the stolen property, bad guys don't always tend to go quietly to jail, and most people we talk to lie through their teeth and swear on their grandmother's grave that they are being honest. It's not pretty work.