So I am lvl 39, halfway to 40 while writing this. I really want advice on who I should focus on and build a team around?
Most used setup:
Chewwie (leader), Jedi Consular, Darth Maul, First order stormtrooper and the last guy I have been switching between different people.

Jedi Consular, 39, 3*, gear IV and abilities lvl: 2-1-1
Kit Fisto, 39, 3*, gear III and abilities lvl: 1-2-1-NA
Ahsoka Tano, 39, 2*, gear II and abilities lvl: 1-1-1-NA
Biggs Darklighter, 38, 3*, gear III and abilities lvl: 1-1-1
Luke Skywalker, 38, 3*, gear II and abilities lvl: 1-1-1-NA
IG-86, 38, 1*, gear II and abilities lvl: 1-1-1
Darth Maul, 37, 4*, gear III and abilities lvl: 3-3-NA-2
Grand Moff Tarkin, 37, 4*, gear II and abilities lvl: 1-1-1-NA
Lando Calrissian, 36, 4*, gear IV and abilities lvl: 1-1-1-1
Chewwie, 36, 3*, gear IV and abilities lvl: 1-3-1-3
Jawa, 36, 3*, gear II and abilities lvl: 2-3-1
First Order Stormtrooper, 36, 2*, gear II and abilities lvl: 1-1-1
Geonosian Soldier, 36, 1*, gear II and abilities lvl: 1-2-1

Cheers!