Coming off the planes you come in the same halls as those going to the planes use.
All of the airside that is 'non Schengen' is connected, if by a long(ish) walkway.
That means that the first to arrive can go to the gate used by the second to arrive and meet there.
Although at most of the airside space is open, there might be some parts of the airport still locked off by security for the whole of the area.
In that case you will be able to meet just outside of the security check for the area of the airport.
Arriving plane gates are not announced so you will have to have your phones at the ready, call as soon as the gate is known. And sometimes passengers are bussed into the airport and might arrive at a door very close to passport control.
If you ask your flight attendants, it is likely that they can include the information in the 'welcome to Amsterdam' message, but otherwise you can see it on the outside of the airport buildings as well as on the signs within the halls as soon as you come into the buildings.
Remember that you might have to go to different locations of the airport to collect your luggage.
You do not need to use a particular part of passport control, and you are free to walk from one set of luggage carousels to the other set, and you are allowed to pass out of the secure zone at any of the exits.
Both of your flights are from outside the Schengen area.
If either of you had come from within the Schengen area, you would earliest be able to meet at the luggage carousels.
This answer is from personal experience, having used Schiphol many times, but for within Schengen as out of Schengen flights.
And I have met my friend in luggage reclaim on some airports myself.
If you have people meeting you outside the secure zone, you might need to call them which exit you use (based on which luggage you collect last) or arrange to meet them at a set point in the airport.
Based on the answer by @EcD, the area at the top of the stairs/lifts to passport control, on the side of the airport where the flight from China is using the gate, is the most likely point.
But I am not sure as I never arrived from a 'non clean' area. Luggage reclaim will certainly be possible, as those are for all flights in two huge halls.