Some more stuff, as it comes to mind…
After you walk in the door and do the gift stuff, you will likely be led over a few feet to where the bride and groom are standing in (typically Western) wedding garb, for a photo. At this point (and probably long before), both bride and groom are already exhausted (it’s a long and full day for them, but with more to come). So, for this reason, I’d not do the “fashionably late” thing too much - they need everybody signed in, relieved of cash, and photographed ASAP, because it’s a full schedule.
You’ll then be taken to your table.
The Vietnamese receptions I’ve been to have been in the order of 100 - 200 guests, and so logistics is a pain for them (I’ve been involved in that side too, for my sister-in-law).
Typically, the reception hall or restaurant will provide a banquet of ten to thirteen small dishes. The food is usually western-friendly: there will be lobster, shark fin soup, fried rice, and some other stuff I forget. But if you’re entertaining worries of dog, snake, tongue, etc, don’t sweat. There will be lots of beer and lots of cognac.
Through the myriad of speeches, dances, toasts, etc, the poor, exhausted couple will likely disappear and reappear several times, each time dressed differently in various modes of Western and Eastern wedding and evening gear. If the money has not been spared, there will be an MC and a live band (playing well-worn English language love standards). Or it could just be up to the parents. There will be a part where the couple toasts one another with garishly coloured cocktails with arms linked elbow through elbow. The first dance is ALWAYS Unchained Melody - in case you were in any doubt. Then the dance floor opens up to everyone else, and there is invariably a conga line at some point. There will be a toast with lucky crackers. There will be multiple toasts, in fact. Some Vietnamese men will get rat-arsed and messy on the “free” XO - that’s a given. But they won’t cause trouble. People start making their excuses and slowly drifting away at 10 or 11pm (earlier for those with kids or the elderly).