The map above also shows a customs exit roughly opposite doors 5/6, so depending on the baggage carousel used, that may be the closest one. I would suggest meeting around door 7 as it's between the two exits and will be less crowded than the official meeting point at door 4.
Don't worry about the greeter's access, they can walk up the main walkway, the one behind the escalators etc or even outside of the building to get there. No-one is going to stop them.