My friends have done it before, they just went to the local police station and got a letter from them that says the photocopy is valid. I assume they still do this, but I’m not sure.
I’m guessing the people in other pre-booked transportation wouldn’t want a stranger joining them anyway because if (and I hope this doesn’t happen) you end up testing positive then they will have to isolate as well because they were a close contact with you.
officially, no. The idea is that you’re not supposed to be mixing with other people because you’ll still be waiting on your results from the test that you take at the airport. That’s why the transportation needs to be SHA+ as well, since that means the driver is vaccinated and meets other conditions.
No. If you’re arriving internationally under the sandbox model you need to take an SHA+ transportation option directly to your hotel. If you contact your hotel they should be able to arrange it.
You’ll be fine if you leave before, the under consideration stamp allows you to stay at least until the date on that stamp. As for when to go back, you could try and go earlier but they may not have finished processing your application so it may be a waste of time. Better to go back on the day on the stamp.
It will likely depend on the airline, especially if you are transiting through another country. If that country does not accept certificates of recovery then I’d assume the airline won’t accept it either. Best to check with the airline directly.