The L2 point is about 1.5 million kilometers from Earth. The various probes like Webb and Euclid orbit around that point at (IIRC) about a million kilometers. The various probes in that orbit will effectively never interfere with each others instruments.
As for coordination, at that orbit, it's going to likely be the individual agencies coordinating with one another. Every probe/satellite launch gets COSPAR IDs and other tracking IDs through various national and international agencies.
As for coordination, at that orbit, it's going to likely be the individual agencies coordinating with one another. Every probe/satellite launch gets COSPAR IDs and other tracking IDs through various national and international agencies.