It. Does. Not. Mtter. The Same Time.
Bonus first: 1 cancels 2s ability. Then 2's bonus cancels one's ability. There is no ability to do anything
Ability first: 1 cancels 2s bonus. Then 2's ability cancels one's bonus. There is no bonus to do anything
Even easier: NO SINGLE BONUS, NO SINGLE ABILITY here does anything apart from cancelling both of the before mentioned. On both cards. It does not need to be applied. It can be completely ignored.
AS soon as any one card has "Stop opp bonus" and "stop opp ability" (in whatevever field) it reads like: "No single bonus and no single ability will work in this round".
Seriously, what is so hard about that? Play through every order of application from same time to one before the other... you will get no effect because the abilities/boni in question just affect the abilities/boni. In fact you can pretend they do not cancel out anything. Nothing of them has an effect on the game. They can ALL work at the same time, not cancel anything, and would STILL have the same effect, which is 0.