The numbers of missing children is astounding.

Are they. And what, specifically is the "Astounding" number?

I found some statistics for Europe.

https://missingchildren.ch/en/our-actions/studies-statistics

Of those reported missing 35% were found by police, 30% came back on their own, 28% were found by a third party, and 7% some other way. That leaves a whopping 0% that might have been sacrificed by satanists.

https://duckduckgo.com/?q=Dutch+banker+child+sacrifice

Seems to be one guy told a story once. Googling his name doesn't return any results for staff at a dutch bank. I suspect the story is made up out of whole cloth, including the claim to be a banker.

https://en.wikipedia.org/wiki/Bank_for_International_Settlements

Yes, they exist. Note that they're neither above the law nor particularly powerful in terms of setting any policy. Their members may consider their advice, but national politics also is pretty important in national monetary policy.