Best first Chromium pull?

Old Ben is not bad, but he's an easy farm, and generally not the monster early game that Baze is. If you want 7* Old Ben, you can get him with about two and a half weeks' cantina farm. If you want 7* Baze, that's several months of hard node farm after you hit level 85. A Baze unlock saves you a huge amount of zots, and gets you a stars long before it would normally be possible.

Also, pretaunt is a mechanic that's normally unavailable until much, much later.