It should be fine.
I’ve had a couple of experiences where we’ve had to downgrade part of the fam during IRROPS. If you can’t OLCI on the day of travel, don’t sweat it. An agent can make the necessary PNR notes at the airport. One occasion, there was one seat left in F. Despite my offer to sit in Y with my son, my wife insisted on doing so. I still hear about it, so I STRONGLY recommend you give the F seat to the wife.