Which 2 leader abilities active would be most broken?

Bossk and Jango would be my pick

Many combos but thinking on the GL/Non GL combos.

-Rey/JTR would be pretty broken
-LV/Darth Vader or EP would be broken
-JML/JKL or Revan
-SLKR/KRU or Hux
-Jabba/anyone Hutt Cartel with a lead
-SEE would be a weird one to find without breaking up teams. I'd you didn't care DR or Malgus would make that team strong
-JMK/Padme

And these are just some possibilities that exist. Many comps that would be broken if a 2nd leadership was active

The answer is Jabba + Boba.

Jabba lead with +15% TM for every TD that explodes.

Ahsoka + Talia
All that evasion