John, based on you not seeing any difference, then me cutting mine back shouldn't make any difference. I need to do a test like yours. Say on one row, cut back all like I like to to tidy up, and that would be probably be August sometime, just to see if those still bloomed okay. I do know that I cut back most, and my yellow rebloomer, and one of my seedlings, both still have sent up bloom stalks now, so the cutting back didn't affect the yellow rebloomer, and I don't know if the seedling is a rebloomer, or it is just coming to maturity to bloom at this time ??, but it didn't affect it from sending up a bloom stem (don't know that either will make it now though this late in season).
As for leaves, I don't end up with lots of them in my Iris rows as they usually blow away, but of course some do remain stuck in the clumps. I don't clean those up until spring usually.