What is the minimum altitude over Egmond aan Zee when landing at Schiphol?
Approaches into Schiphol are usually vectored by ATC during the day (see below for night operations). This means the controllers are giving instructions to pilots depending on the current traffic, which makes it hard to say when exactly planes will overfly Egmond aan Zee.

If the Polderbaan (runway 18R/36L) is used for landing from the North (18R), planes will be vectored to the PEVOS waypoint shown on the following chart (source: Jeppesen):

At this waypoint, the aircraft should be at an altitude of 2000 ft (about 600 m):

I marked the approximate position of Egmond aan Zee on the map. There is no given minimum altitude there, so planes could already be at 2000ft, but they are likely still higher (3000 to 4000 ft) see below for update.

During night operations, Schiphol is a lot stricter about where planes can fly and how they can descent. The following night approach chart shows how planes will fly if they land on 18R:

Egmond aan Zee is between EH602 (where planes will be at FL70 or about 2100 m) and EH607, which is on a dashed line indicating a continuous descent path, where planes must fly at idle thrust from FL55 at NIRSI down to the ILS intercept altitude (2000 ft).



I just had a look at flightradar24.com and saw a KLM Boeing 737 flying quite close to Egmond:

According to the ADS-B data, they were between 1800 and 2000 ft when flying just south of Egmond an Zee (I marked the point where they leveled off at 1800 ft). I assume this data is somewhat inaccurate since they should not descent below 2000 ft before intercepting the ILS. Other aircraft were also at similar altitudes around Egmond, so I assume overflights at 2000 ft are quite common.