So I saw someone post their predictions for the next event and DF, so I'll do the same.
The next event HAS to be a mixed event. 1, because we've had WAY too many full band events in the last couple months; and 2, because of the announcement of a HHW cover of "We Are!" This also means that at least one HHW member has to be in the event.
In terms of cards, one of the 4 stars, either in the event gacha or the DF, HAS to be Kokoro, and another one HAS to be Ako. For the other two, there's Sayo who hasn't had a 4 star since February, and there's Tomoe who hasn't had a 4 star since February.
Now let's look at what the ideal other members would be (this is IF this event is the most ideal event, which it probably won't be). Yukina would ideally be the gacha 3 star, since she hasn't had a gacha 3 star since JANURAY 2018!!!!
For the event 3 star, ideally, Tsugumi would be the event 3 star, since she hasn't had one since February 2019.
Finally, for the event 2 star, it would ideally be Saaya; she hasn't had one since January 2019.