Question: Let's say the USA and China get in a spat and things escalate to a trade war or a shooting war (unlikely, outside of Tom Clancy (RIP) novels). What happens to the huge amounts of property owned by Chinese nationals? Is there some precedent for seizing it?

I would guess that the historical examples would be WW2. Which is problematic, because we put people of Japanese descent in concentration camps, as opposed to nothing for German/Italian immigrants...