WR250 2 stroke is a great choice with its larger tanks and wide ratio transmission. This is the bike I ride. The only thing you will need is a flywheel weight so you can lug the engine to lower RPM when needed and make it less responsive so you don't throttle over something or spin the rear when you wanted traction. The WR426f would be my second choice. BTW I am 6'2" 240#s.
The YZ and KX's have small track tanks and are designed for quick throttle response with it's close ration transmission. They are great track bike but not a great woods bike choice.

The 250 4 stroke bikes are equivalent to your old 125 2 stroke. Probably under powered for a 200# adult and the wrong kind of power for trails.