I would go ahead and gear vader, tarkin, and tfp at a minimum. They are useful in many areas and will help your fleet a lot. If you run tf, vader, and ht under tarkin in your starting lineup and some decent reinforcements you'll do better in fleet arena and get more zetas and crystals to use on hearing other characters.
The gear investment in a great arena squad and fleet arena squad pays off. I get about 1000 crystals a day from both arenas. It really helps fuel my other projects.
It actually has helped to the point that I'm out of projects until the next legendary drops. So just stockpiling crystals at the moment.