Himeno values Aki's well-being. Their bond may be very close, but it was never mentioned that she was in love with him, their relationship is nothing more than co-workers. I hope I'm not wrong and if so, I'll have to read the manga again
I understand Kobeni, but I don't see Power getting into a relationship, for me that's the same thing as the last order dating Accelerator, well that's my opinion.