how can i find out about people deported to the netherlands?

Answer 1

Since deportation, extradition etc. are primarily a concern of the state that actually does the extraditing, I'd start there.

Unless there are reasons (Dutch or international criminal record, search warrants, persona non grata) to detain an extradited person upon arrival, the Dutch authorities are under no obligation to keep track of that person provided the entry papers (id, visa etc.) are in order. A person may be held under surveillance if there's a reason, but such details of course are not disclosed to the public.