I had everything printed (and would still recommend everyone do so) but they only looked at CoE & pre-flight PCR in addition to the passport & arrival card.
They never asked for T8, Shaba Cert, vaccination card, PCR test results or insurance. Had all those ready, though.
Sharing should be fine. You'll likely need a SHABA/AQ cert for each person, but it can be under the same booking (make sure to clarify with your accommodation)
"Exemption from Quarantine" scheme says "1 night OR negative test result."
I suppose it's a bit nebulous what "1 night" means, as someone could stay over the midnight hour, but at least you can presume much less than 24 hours.