User blog comment:B214/Question and Answers 2/@comment-187.195.197.49-20140430172611/@comment-1359322-20140501135412

I think Akeno would fit that role more than Irina especially since it's lightning.

And no Issei hasn't have any Oppai related power-ups for the past few Volumes. I think the last time he had one was Volume 11.