That's the $64,000 question because it changes all the time and so is incredibly challenging and frustrating. That being said, the trend is definitely toward the opening up of consulates in general and to third-country nationals in particular. Many of the US Consulates in Europe, for example, have opened up. We're also seeing a positive change as a result of the lifting of the travel ban on November 8th. Regarding Canada and Mexico, there's been no announcement but I suspect soon - and Mexico is accepting TCN applications but only on an emergency basis.
2/ When will Canada and Mexico allow that?
PS: It seems impossible to get an appointment in my home country.