Its just a regular name like everything has a name. It describes the shape and approximate location.
I do not think so.
In an indirect way. The Bermuda Triangle is an area of the Atlantic Ocean within the points of Bermuda, Miami and Puerto Rico.
No. The Bermuda triangle is by Florida in the Bahamas.
The people there undoubtedly know about it, and probably know it was more or less made up to sell books and newspapers. Given the weather and amount of vessels in the area, what turns up missing is...