Some more on set pictures:
At least some of the episodes featuring Superman will take place in Metropolis, which makes sense:

This is presumably Lena Luthor's company, as she's been cast as a recurring character for the series:

Kara and Clark disgracing the Superman IP by smiling:

It appears that Metallo will be showing up in some form:

And as a result, Kal-El seems to adopt some kind of anti-Kryptonite fancy harness:

But it looks like he needs help from Martian Manhunter to take down Metallo:
