Zod and Scorpion are smart moves
Though I would have prefered something like Red Tornado, Martian Manhunter, Zantanna or even ones like Atrocious, Icon or Black Orchid.
but Zod and scorpion are smart bussiness descisions since one is from the upcoming movie and the other can attract MK fans.
Well, the first season batch of DLC characters have pretty much been confirmed, however that is only the tip of the iceberg;
Game Developer Ed Boon has posted a poll on twitter, asking Injustice players who they'd like to see turned in a DLC character. The poll had Red Hood, Blue Beetle, Zatanna and a few others. Boon went on to say that he knew that the majority of fans would vote for Martian Manhunter now to be a DLC character, and so felt it would be a waste "To include him now".
Basically, from this, we can gather;
-Martian Manhunter will be a DLC character (Probably saving the best for last)
-Red Hood, Blue Beetle, Zatanna and a few others are being considered as DLC characters for the next season
-The Season Pass will indeed be very beneficial, and won't just have one DLC character group; it will be continous
I don't have a link to Ed Boon on twitter, but you can check it out if you're interested.