Additional/Day-Of FP+ for Group Members Arriving Later

[disqueen11]

During my upcoming WDW trip, one member of the group will be attending a conference, so won't join the rest of us until later in the day (around 4 pm+). Our group anticipates using our 3 advance FP+ by the time he arrives. When we go to schedule our additional / day of FP+, will we be able to schedule them for the friend arriving later? (He is linked / friends through MDE).

Any other advice for FP+ and groups with members arriving later in the day?