Dogasu nabbed a magazine interview from back when PM returned from its hiatus. A Festival Reunion! was when the staff made the decision that they were going to bring past characters from OS-SM into PM
given PM's setting (Ash traveling around the Pokémon world).
Yeah. I still hope Iris returns at some point since she was robbed of a cameo appearance in XY. xD
I think the dual episodes are gonna stay, but they're just gonna be hit or miss. But we'll see how that goes. xD