Did any WW1 or WW2 German officers actually went to study at Westpoint?

Answer 1

No. No foreign service officer has ever trained at one of the service academies.

There have been foreign graduates of the service staff schools in the US. Just as American officers have Graduated from Foreign Military Staff school . Patton Graduated from St Cyr in 1906 where he had gone to learn French Calvary Tactical Theories.
Marshall went to British and French Staff Schools in WWI to Learn how the allies fought the war. And Marshall sent an officer the Kriegs Academy in Berlin in 1937 for a year when he returned he wrote the manuals that mobilized the American Army in WWII.

The Hitler would not have sent any of his officers to a US Staff School because like most European Military Men he believed that the US had everything to learn from Germany and Germany had nothing to learn from the US. The US was looked down upon by the European Armies until about 1943 the Brits even considered the US Army as just slightly better than the Italians.

Answer 2

The first to answer is correct. Realize that Germany has say ten "West Points" for training officers. I can locate before WWI and up to WWII West Point cadets from such as China, most all South American countries and of course the Philippines.

Seems it would ruin a Germans career as they would miss all the networking required in becoming a functional officer.

Possible, yes, but you have to realize France was fighting Germany in the late 19th century and such. I suspect there
were cadets who were born in Germany perhaps one went back?

Who knows would be a good topic for an author to pursue.

Hope somebody digs some more of this.

Answer 3

It was actually more common that generals would have studied other subjects at other American universities (economics, engineering, etc). West Point had allowed non-citizens, but it was usually from American possessions such as the Philippines.