In a similar situation using a 2for1.
Have a party of 5 on a total of 4 PNRs. The 2for1 is a complete open jaw round trip on one, while the other 3 are one way redemptions, as we're split across two flights on the inbound.
Only issue is admin, ie seats etc, as I'm the one who gets dumped with sorting out the detail of flights.
You First were no bother in booking a Cabana for the earlier arrival time as I supplied them with all the PNRs