Regarding the US visa, my C1/D is annotated Emirates Airlines and I use it 3 times/month to enter the US without any problems, just like I used to do with my previous C1/D when I first started to work for EK and my US visa had my previous employers name on it before it expired and nothing was mentioned either by US border control...
In order for EK to cancel that visa they would need to send your passport to the US embassy which they don’t do...