I don't think they exist because when I play with my Cover Woodson - my LBs/S's get outrun where they shouldn't.
I also don't follow how they would be able to program in these boasts if they aren't included in the depth chart/base player stats. You'd need a seperate line of code that references these boasts. That's a lot more - unnecessary coding repeated every time the game references a players rating. I also can't see them programming this in the regular gameplay since it's all ran on the same model. The game wasn't built for ultimate team mode or these boasts.
I don't play MUT and Fifa but I believe in these modes the boasts are shown in the depth chart. If so that gives further evidence to my theory.
I could be wrong though and welcome any evidence or opinions otherwise.