IRROPS could be tricky for sure. There will most likely not be enough J seats on a single plane to move you all to. It's likely your party would be broken up onto different flights. How they handle fare paying J passengers vs. non status award ticket passengers will also vary. Not something I'd really think about until it gets closer. Giving yourself the week buffer before wedding should alleviate most concerns about this. Just know in the back of your mind that some may wind up on a different flight downgraded to coach or premium economy. It all depends on the loads at the time of the flight disruption.
That's what we are discussing. Everyone in my immediate family is EP, including the spouses of my two kids, however, to your point, last minute moving of 17 people all in J would be very problematic regardless of status, but the EP might open up the other airlines (wasn't sure if award travel was different though). My wife and daughter are deadset on us all flying together which in a perfect world fine, but it's not. I would prefer if we were not all on the same flights. Put the friends of my daugher on one flight, wife and I and some family on another and so on but I may lose that battle. Technically, our company prevents more then two high level Managers from being on the same flight, of which myself, my wife and my two children all are, however, it's our company so it's kinda of a moot point (it's my rule to break lol) but to be fair, once our kids became operating partners, we have never travelled on the same plane as them and we hold our staff to it so I may try to fall back on it. Will see.