You all have the patience of saints.

Alan Marshall there IS a wealth of info - this question is asked all the time and there are many many posts with helpful responses for you to peruse.

I haven’t flown this route, but have flown EVA (among many others). It is almost always the case that if you really want to sit together and you care about your seats (do you mind sitting in the back of the plane?), you should pay for the seats you want. Doing so makes the question about when/where to check in moot, since you will have your seats already confirmed, but checking in online as soon as it’s available increases the chances that things will go smoothly. That said, if you purchased tickets together and are on one confirmation, you will PROBABLY be seated together. No guarantees, though, unless you pay for seats.

Not going to happen, dude.

The answer clearly depends on your personal level of risk-aversion...

When it comes to immigration matters, best to start with an official source, not FB.

Your friend should get his information from official immigration sources, not from FB through you.

Sounds like you should be glad that you were able to enjoy the loophole for some period of time.