Well the whole will there be an evolution or not, in context of the episode's focus.
Well there's just one problem, if it was Kiawe centered then the "evolution" would have to be symbolic, because none of Kiawe's Pokemon can evolve.
Ash could evolve Torracat, Rowlet, Poipole, unfortunately the only one that seems likely at this moment would be Rowlet, and even then I doubt Ash would get an evolution episode immediately right after a Torracat centric episode.
Lillie evolving her Vulpix now seems kind of weird, I would get wanting to give Vulpix some more extra screen time, but a few episodes after it initially refused to evolve, seems way too much.
Lana's Popplio could evolve, but seems unlikely at the moment.
Sophocles can evolve Charjabug but doubtful since it requires a specific place, and unlike Popplio and Steenee has no reason to evolve through the use of "dancing" at least Popplio has "performance" link to dancing as in "singing is close to dancing in terms of performance levels" unlike say nothing.
That leaves Mallow and Steenee, and unlike Popplio would actually be far more likely to evolve, because at least Steenee could be similar to evolving through dance, it evolves with the move Stomp, which could in terms of a Pokemon story could be a dancing move, since I'm sure some dances incorporate stomping in some aspect. And with Tsareeena being a Pokemon into kickboxing, one could argue in terms of performance a kickboxer would have some fancy "dance" like moves.
So really the only choices I see are (if something happens): Ash's Rowlet, Lana's Popplio, and Mallow's Steenee.
And since the photo is of Mallow and Steenee having what looks like a more amplified close interaction that doesn't typically happen in a random non important episode (as in Mallow getting down to Steenee's level while Steenee could be considered making a Dance like pose, such as an after dance pose), I'm just pretty positive it's far more likely to be Mallow's Steenee evolving over anyone else, but hell if Ash's Rowlet evolves in a dancing episode right after a Torracat episode, that'll be cool, and if Lana's Popplio evolves, well here's hoping Lana gets Primarina down the line.
Otherwise nothing interesting is going to happen (at least in terms of major development).