...Ace would not directly harm Ichiru, because he knows that would be a bad idea and that Zero still loves his brother (though he thinks it is super fucked up above and beyond his own weird take on things and that Zero would be happier if he just got over himself and shanked Ichiru post-haste). But he would be wary and passive-aggressively hostile towards him and...I'm not sure there's anything that would ever be able to change that. I think the deck's already stacked too high against Ichiru in Ace's mind.

Eventually he might take Ichiru aside for a talk :) about how much Zero means to them both :) :) and how much Ace doesn't want to see Zero hurt in Aather :) :) :) especially not if it's Ichiru's fault. :)

Reverse for Zero?