You are trying to write software to make wrangling drunk people, shooting people of vastly different ages, and people who either have a strong desire or no desire at all to be a part of the pictures at all; easier to do? I want to stop you right there.

Your best options aren't software related. They start with setting expectations with the couple at the initial consultation, reinforcing that with each contact, having a set amount of minimum time in your contract to capture necessary formal shots, and finally by being in charge the day of and knowing how to effectively manage groups of people. Additionally you can bring a second shooter/assistant to help with larger weddings.

Finally, I'd encourage you to stop the practice of asking the couple's for a shot list. Those images rarely sell when it comes down to it, they take a ton of time, and in my opinion are just plain boring to capture. Instead, ask couple's for any shots they consider must haves, for example of the bride and her aunt she hasn't seen in many years. This sets the expectation that those are the must have shots not 60 different family formals.

If you find out that a couple does want each and every formal combination, the best practice I have found is to take the largest group photo first, and start taking away as few people as possible for each successive shot. Don't take small group formals first. Also consider ages, don't make the most eldest join for a shot, get pulled out, and back in a bunch of times.

I could go into more detail but this has already gone far beyond the scope of "software to achieve this". Just understand that technique, preparation, and experience can alliviate most of the issues on this topic.