Trimming down that clarification in the OP to bullet points may help those not so into reading, so there are fewer blow-ups.
- The Ultimate Edition included the Season Pass and full Halo Wars Remastered
- In addition to the leader add-ons already released for the Season Pass, two new leaders (Jerome and Arbiter) were announced at E3. Two additional leaders will follow.
- Two new story missions which branch off the main campaign will be released for Season Pass owners.
- Today's announcement is a new campaign, complete with new cinematics by Blur Studio, with new multiplayer modes including Solo/Co-op survival Firefight, and a new set of heroes. These will be released after the last of the Season Pass content is released, and isn't included. It adds on to the main game.