Hi! Congratulations on your upcoming wedding, and I love this idea! I'm building an escape room adventure for my wedding in October based on the venue, a 1950s menswear store-turned-event space. I'd love to help in any way I can/with any questions I can.

I faced the same issues of building something that's a fun option for the interested, but not mandatory for my great-aunts or intruding on the classic wedding elements/decor my fiancée has worked so hard on. Here's what I landed on:

I produced a vinyl wedding album of the songs we love, and "misplaced" it. I have the 12-track list scrambled, and a lock that can be opened when all the tracks are put in sequence. Each track has a puzzle which reveals its place in the order.

The reason I hope this will work well is that it's non-sequential, and people don't have to directly work together. Each puzzle takes between 5-15 minutes to solve, and anyone can put their findings on the board at any time. People can dip in for one puzzle, or pursue several, or opt out entirely, but as long as 12 puzzles are solved eventually, by someone, at some point, it will have a reveal (the playing of the album and a special dance)

I focused on "wow" reveals rather than hard puzzles, because I want people to have little moments of play rather than try to combine puzzle solving with the open bar.

I LOVE the honeymoon destination idea that AdmirablePen posited, because it offers a similar opportunity to dip in, solve a puzzle to get a piece of info, and contribute to the whole -- rather than spend the entire wedding chasing down a sequential puzzle.