Ok, so now I'm confused!
Am I to provide her DL# if he asks?
As far as the passport goes he was previously ordered to turn in his passport due to child abduction prevention orders. He was to notify the Dutch Consulate within 60 days but never did. That's why he was able to leave the country 5 years ago.
He was recently again ordered to turn over his passport but there's no way of knowing if he has. There is a no travel with children which specifically states he not take them from the county as well. Couldn't he get a passport with her documents?
I absolutely would not give him the driver's license number. He has no valid need for it and he could very well insure his car under her name once his Driver's License is yanked. If a judge actually orders you to give it to him you will have to, but until that happens I would NOT do it. Of course, he may talk your daughter into giving it to him.
He can get their social security numbers and birth certificates without you. (assuming that he is on their birth certificates).
He cannot get a US passport for them without your notarized signature. I have no idea if he could get a Dutch one for them without your signature, but its unlikely and you could verify that by contacting the Dutch Embassy or Consulate.
Actually...scratch that and double check with the State Department and the Dutch Embassy. I seem to remember that for kids 14 and older it does not require a parent's signature on the passport application, it simply requires their signature. However I am not sure that I am correct about that so do the due diligence and verify it with the proper authorities.