You shouldn't determine how much you charge by how much you need to survive, but charge instead by how much the company can afford to pay, or how much they're going to make (harder to determine the latter).
After all, the company doesn't price its products by how much it needs to stay solvent, it prices them by how much they can get people to pay.
Let's rather put it this way: the company saves money; if they give some amount of the savings back to the employee (via salary), both sides should be satisfied.
Yes. I work remotely from Uruguay. It´s basically the only option to compete with U.S. talent, the whole point of remote work for the company is to get the best talent at a price they wouldn´t get in the U.S.
I know that if I get an H1B visa or whatever my salary would immediately go up. Location and salary are unfortunately correlated (it´s not even cost of living, Uruguay is more expensive than 2/3rds of the U.S.).