I see it happening extremely similar to how you say.
Only that Mel does survive. They've shown too much to hint that she's gonna shield the blast for her, Jayce and Viktor.
Viktor/Jayce divide will no doubt come about related to how you say, but as Viktor has already asked Jayce to destroy the core, I don't think their would be conflict over that aspect.
More so that Viktor is injured by the blast so has to embrace to Hex-Core against his wishes to survive.
Hope once he does take Zaun's side we get to see him interact with Jinx. Subtle hints that he respects her engineering make me think they could meet up in S2.
Also think Warwicks reveal would be more dragged out. If they stick to the 3x3 format then he'd be a good bet for a reveal at the end of the 3rd act.