I’m assuming you mean the comic characters and not the actor and actress. I’m not super duper familiar, but this is what I remember:

Big Barda was originally a part of the Fury’s under the direction and training of Granny Goodness (denizen of Apokolips) who words under Darkseid. She eventually becomes a hero.

Mr. Miracle is also a New God and like an expert fighter and his biggest power is being a master escape artist/being able to escape pretty much anything. Also becomes a hero at some point.

So, it sounds like we’re getting some New Gods and Apokolips stuff if they’re bringing in these two.