Business class and economy checking in together

My wife and I are flying SYD-SIN-SGN-HKG-SYD all in J class whilst my adult (20yo) son is on the same itinerary/flights in Y class. Do you think the airlines will allow us all to check in together at the Priority Checkin? Would rather not check in and then have to wait for 45mins whilst son works through the economy queue before joining us.

they will let you use it together based off my experience

You shouldn't have any problems, I've done it quite a few times with Qantas. I always think of it as having the same rules as lounge access, as a Business Class passenger, you can bring a guest to priority check-in, just like you can bring a guest to the lounge. (for the airlines that have this privilege)

I've never had a problem, even with non-family members (e.g. colleagues). Within reason though, one person is fine, whereas a group would be inconsiderate.

No problems.

You could always upgrade your son to business!😆😆😆😆

I have never had a problem with this, nor have I ever had a problem when checking in a family member at a ticket desk to which I would be entitled with my home FFP airline - so, for instance, if checking in my daughter to a flight on CX (where I have top-tier status) I would go to the F check-in desks, flash my Diamond card and check my daughter in there. Ditto for MH.

I have not had such problems.

In fact sometimes when travelling economy and lines are busy Ive been directed to check in at Business