[2021] Nien Nunb and Greedo weren't originally planned for the Outer Rim DLC. But the Devs wanted there to be two heroes for it.

Sure!

Outer Rim - Chewbacca and Bossk (originally only going to be a Sullust-only pack depending on other stuff, read below)

Bespin - Lando and IG-88 (rigging a droid character was going to take too long, so Dengar replaced and all bipedal droid characters were moved to SWBF2)

Death Star - Obi-Wan and Tarkin. I can't fully recall why we didn't do Tarkin, maybe it had something to do with the character going to be showing up in Rogue One later on.

We weren't sure that Rogue One DLC was going to happen, so backup plan was R2D2 as a full-on hero instead of a game mode objective replacing Obi-Wan on Death Star and Obi-Wan headlining a Mos Eisley pack for Battlefront 1 likely with Greedo (since Rogue One did happen, Mos Eisley was instead moved to Battlefront 2).

When I joined SWBF2 development I then realized they still weren't doing Obi-Wan so I flipped. As you probably noticed at EA play, I was quite satisfied with Obi-Wan finally joining the game. :)

Oh, really early. And as much as IG is this fan-favorite-mystery-droid, I thought the Dengar thing turned out great. Simon Pegg was amazing and machine gun Dengar was so much fun to play.