Alt Keldeo forme.
1.Meloetta's formes are on the same page(Not too helpful of a hint though)
2. GF told us to use the event Keldeo in B2W2 but said nothing about BW(even though there was a Secret Sword event in BW). Why would they tell us to use it in B2W2 then ?
The place holder thing can be done the same as they did with Spikey Eared Pichu.