How do I edit video footage from an interview?
There is no one right way to edit anything. I've never watched a video of this kind so I probably can't give the best advice. But if I was in your position there are a few ways I'd consider cutting it together:


Edit it a bit like a 'behind the scenes' video. Begin with footage of someone talking and then use appropriate cutaways of the wedding. Cut back to different people whenever it is appropriate and put some music underneath, something that fits the mood.
This would be my preferred way but you'd need a fair amount of footage of the actual event and even some archival footage or photos would be very handy. Most movies have a behind the scenes on the DVD so I'd suggest watching one or two of those if this method sounds good to you. 
The simplest way would be to show each interview one by one. So you'd show the first person's interview in its entirety followed by the next person's, and so on. Crossfade between them and have music underneath. This would probably be a boring video to watch in the end, but it'd do the job.
Similar to my previous suggestion, this would require only the interview footage (no event or archival footage). However, you'd intercut the interviewees based on topic. For example, if the bride talks about how she met the groom you'd intercut that along side the groom talking about how they met (assuming he does). This way you would be able to cut out a lot of the fluff that you get when interviewing people.


That's how I'd go about it anyway, mate. Hope that helps you out a little.