There is a repacking area in the lower level of Schiphol Airport. I have not used it to unload, but we packed our bikes in the area at the end of 3 tours there. I don't know for sure, but it probably would work for unpacking your bikes as well.
We have unpacked our bikes at 4 different airports; Lisbon, Copenhagen, CDG, PDX, and asked at the airport information desks where to leave the boxes. We were told what to do with the boxes. Be sure to ask someone, they don't like unattended luggage sitting around.
We use ultalight duffel bags to carry our gear, which are checked, and the empty panniers go in the bike boxes. The duffel bag is used on the return flight home.
It looks like a garage sale, but everything fits in the rackpacks and duffel bags. This is on the lower floor at Schiphol.
This is at a train station, but the operation is still the same. The bike box and duffel are checked, the rackpacks and bar bag are carry on. The empty panniers go on the bikes in the box.
Also be careful with your bikes if you are actually riding through Amsterdam. There is a bike path from the airport to some motels close by. We get a room, secure our bikes, and then take the motel's shuttle back to the airport. The train station is on the bottom floor of the terminal, and goes right into Amsterdam. It is a lot more fun to wonder around town without the bikes. The figure I heard was 185,000 bike a year stolen in the Netherlands a year. Boy was I wrong!
Bike theft in Amsterdam