Hello, 2 part question so wondering if anyone could shed some insights?

1. I am flying CX J from NRT into HKG, arriving after 10pm. I have my next flight also in CX J to TPE next morning at 8am. so roughly a 9 hr layover between landing and takeoff, and not really wanting to venture out of the airport. Any recommendations on which lounge(s) I could use? i'm OWE if that helps too

2. I have a travelling companion on the HKG to TPE flight next morning. Could he arrive at HKIA around the same time as NRT arrival, check in and join me in the lounge(s)? any complications on checking in late night the day before?

thanks!