LotF 33 50 Han Solo, Galactic Hero
TFU 45 45 Garm Bel Iblis
AE 37 45 Mara Jade, Jedi
LotF 14 9 General Dodonna

Preferred Reinforcements: (30/30)
# * Cost Name Type
LotF 11 17 Bothan Noble Garm
TFU 22 13 Rebel Trooper on Tauntaun Garm

is this viable?

Pretty low on activations, even for a Dodonna squad. Your damage output is nice, and having the Tauntaun in there for better chances at winning Init is always great. You'll be in big trouble though if you still don't win initiative. And against tough pieces like Lord Vader or Darth Tyrannus, if you don't kill them in one round with Mara/Han, you will probably lose Mara or Han in return, which will hurt. Overall, unless your LGS is uber-competitive, this should do just fine.

Except for Garm's CE not at all helping.. thus you're basically wasting those 15pts. i'd drop Garm and go with a few more activations. Find a build that you're really satisfied with.

46 pts is a lot to play with, but there is a lot of options without Garm.