I always forget PLA is made from corn. so when people ask if its food safe I can now say yes it is, because it is food 
lovely
I know China ain’t directly affected (or very little) by the Middle East or Ukrainian issues for their diesel supply.
Diesel comes from oil. They’re affected like any other country now. Oil is a on a Global Market.
No you can’t. There are colorants, plasticizers, and modifiers added to make it brightly-colored filament with various properties.
There are food safe versions but without specifically using those you may be having various exposures.
Indeed. Not a single commercially available filament is safe for use with food or beverages. Definitely not the usual 3d printing filaments.
Obviously, diesel is refined from crude oil, but it’s my understanding that China has supplying alternatives that allow for lower costs. I’m not saying they aren’t affected at all by the current international crude oil market crisis, just that they seem to somehow keep their internal prices under control and the international crisis doesn’t appear to have the effects it has in the western world.