All of the monitors you are discussing are Aperture grill monitors. Aperture grill is the generic term for Trinitron CRT's. Sony first developed and patented Aperture grill technology and calls it "Trinitron". Trinitron is a trademark of Sony and can only be used with their permission. Mitsubishi licensed the technology and developed "Diamontron". Basically any model, or brand with "Tron" in its name uses an aperture grill CRT.
Sony's patent has expired and companies like LG have developed their own versions of aperture grill CRT's. If the monitor uses FD Trinitron, it is a Sony CRT, if it uses Flattron it is an LG CRT, if it uses a Natural Flat it is a Mitsubishi CRT.
The LG Flattron CRT is unique in that it the only truly flat CRT that I know of on the market today. By truly flat I mean it is flat on the outside and inside. All of the other so-called flat CRT's Sony FD Trinitron for example is flat on the outside and curved on the inside. In real basic terms they simply added a piece of flat glass to the front. The only real benefit that I have found with flat faced CRT's, is some slight glare reduction.
Good Luck