when it comes to eternatus, containment is the only real option to keep that thing out of trouble, so i'm not concerned at all that Gou "Caught" it, because they had no choice, and at least he realized it's too dangerous to keep around like a standard pokemon and allowed them to put it somewhere where it can not cause problems...granted like others have said it's not going to be surprising at all if someone tries to get it back out.
The Evolutions were ok, Riolu's definitely a powerhouse now as it mowed down both of Rose's pokemon by itself with the Hadoken (I was kind of hoping they would've played Aaron's theme when it did evolve, but it's not like i expected them to), and on the other side I see Cinderace is no longer in it's emo phase, and back to being cheerful.
Seeing Ash and Gou with glowing artifacts was interesting, does that reflect their characters I wonder? Ash with the sword representing him being the more "aggressive" fighter, where as Gou with the shield is the more "passive" capturer?
The only one problem I have is that even if Rose did get away, was there any mention of reporting his activities to the authorities? Cause if not...Leon and Ash are going to likely have an interesting remainder of the PWC...with rigged battles likely coming their way, Leon can likely handle it on his side though...Ash on the other hand I don't know.
and it ain't gonna surprise me if Rose sends an emissary after Gou as well for revenge as well.