I am sure down the line it will be part of a dlc bundle for £15, activision have a nack for doing that.
What would be great (for everyone?) I think would be:
1 - Release the maps in a DLC and if you have a HE, the Map pack would be sold at a discount (because you already have part of the pack); or
2 - Release both the maps in on extra DLC so everyone could have it (HE edition users would not need to buy); or
3 - Do what they did in BO1: Have a map pack containing NT 2025 and NT zombies in it and it is free for HE/CP pre-ordering customers
As far as the season pass is concerned, if they do option 1 or 3 above, the season pass would not be worth it for HE/CP buyers. To make it worth it, the NT maps you get for pre-ordering would have to be in a separate, and extra DLC (option 2 above, or something else more ingenious that my feeble brain has not thought of).