My wife and daughter (both no status) are both waitlisted for biz on one PNR (the book X and waitlist I method) for a flight tomorrow. I'm already in biz on a separate PNR. I've seen 1 I seat open up twice now, but of course they don't clear because there hasn't been 2. I'm guessing I want them to split in this case? They would automatically split this afternoon at T-24?
Assuming you are okay with only one of them clearing, then yes. They will automatically split when they check in, assuming the upgrade (waitlist) has not cleared.