Predictions for the Victorious skin
The current pattern goes Top, Support, Jungle, Mid, Adc considering Victorious Maokai was made when he was primarily Top (He still kinda is but jungle and support are played more often now). This leaves us with the Support role for our Victorious skin.
I am going to eliminate Ivern and Rakan from this since they are new and also eliminate Janna since she already has a Victorious skin and maybe Thresh and Karma since they already have a Esports skin.
The current meta has been the Ardent and Shield support meta and the Supports that are included that could be picked are

It seems like Lulu and Sona are the highest up there since Nami and Soraka just got skins recently, but that really doesn't stop them from getting the new skin and Taric didn't make a huge impact as other healing supports this season but, his influence in proplay was large so we don't know.
Lux, Vel, Brand, Zyra and Veigar could also be chosen but this seems a bit off considering they aren't really supporty champions other than Zyra who was only great in a certain meta but she could be choosen because she was also decent in Proplay.
And finally there could also be the champions like Leona, Naut and Blitz who all were decent for the most part this season with Naut being good in Proplay too.
Honestly, we will just have to wait, last year I bet no one predicted Mao.
Are all champs I can see getting it.
would all be really cool but I sadly doubt they will get the skin.
would be a cool pair to give out.