Whether video reviews should be used at all in D3 when they are never used the rest of the season is certainly open for debate.
Right now, in all (I believe) D3 sports, video reviews are used from the semifinals and finals.
The refs aren't alone. They are assisted by an experienced video review ref (usually the same one who does the D1 Frozen Four). So, they are mentored through the whole process as well as the review itself.
I don't know what you mean by change their minds. Of course their minds were changed. They never made the call in the first place. Adrian used one of the challenges to have it looked at.
Chris Schultz was not upset with the call. Though he thought it was a good hit live, he said the video review doesn't lie, so he accepted it.
A hit to the head is five minutes. Period. They had no other choice once it was decided it was a hit to the head.