Iris have ability exchange? Not sure what is it, but with full bloom she can...
+1 Canon shoot to pest. The canon panel in map.
She buff ATK to party and increase active skill use rate.

About you and Myrdin I may refrain from saying anything, except two thing.
If it start for missunderstanding and you willing to correct it just do it.
If you want to move on and don't pay any attention you also can do it.