If you want any of that, you’ll need the whole pass. It’s included with Cod Blops 4’s ‘Digital Deluxe Edition’, which costs £30/$40 more than the standard. Activision will sell upgrades from the base edition to the Digital Deluxe, but not sell any of the content separately.
Committing to a full pass in advance is an iffy proposition. What if the DLC turns out to not be great? What if you’re only interested in some parts? What if you stop playing Cod Blops 4? And what if other people stop playing?
Activision have previously also sold Call Of Duty DLC in four packs across the year, which has been more expensive than buying the whole pass but is less of a commitment. Now they’re removing that choice. Activision say they plan to “[deliver] content with more frequency”, so it could be less clear-cut than the traditional ‘three maps in one lump’. Still, it might work out about the same if they sold access to e.g. Three months’ new stuff. Or if they made new maps free and found other ways to monetise the game.