it's a bug right now so follow me: you talk to cassara at the "Scarlet Vipers" gate (in jimmy's room there's a map on evelyn's picture) -> run the notification to Olivia again -> morning from 8am to 12am in the alley leading to the slums, you'll see olivia's group waiting for you -> then you go to Scarlet Vipers again, go to the room on the right and change clothes, go up to see layla so she can introduce the 2 new characters -> and go down the 2 rooms on both sides of the stairs to practice.
(just because layla's quest appeared at the wrong time)