If there’s 4 people in 2 cars it doesn’t really matter who gets there first just as long as you close or disconnect quick enough.1. everybody talks about the green flash... you mean when the screen gets black and says mission accomplished?
2. is there no screenshot available when to disconnect/close the app?
 Do the heist like normal,
 Host wait at the buyer and the friend(s) wait somewhere near the buyer but still have the objective to deliver.
 Host get ready to quit the application and get your friend to drive over.
3. if we are 4 people with 2 cars, should the friends car already drive to the yellow point or should the host in a car with a friend drive there first?
I wait for the take to disappear before I close it’s never let me down. I provided some screenshots for you to check out.