I think that, despite 4.x being SH's time to shine, not all SH members will appear.
Elio and Kafka are probably a given since it's long overdue.
Blade is tied to space china while Firefly and SW got quite a lot of screentime from both the main story and events.
I bet they're gonna give us some lame excuses like Elio suspended their activities or he sent Firefly and SW to school.