Yan isn't impervious to getting jabbed
and font splits the guard really well with front up kicks (we've seen this him in several fights, including hurting cody with it) and he splits it well with uppercuts, he also punches around it well with hooks. Font kicks more in general than yan, too. I think it works both ways: they're both meat and potatoes types guys, but they're both better at it than anyone else they've faced.
TJ doesn't have more volume than Font. Font averages more than TJ per minute. Sandhagen has a bit more volume than font, but Font has more power.