Please help my squad development, I went down the random line! Need to salvage my squad advice.

Thank you Stealth! I'll look up that guide and take your advice and go down the Phoenix line. However,
since I'm a free player and have to grind this all out, what do I do with my other team members in the meantime...do I just minimally upgrade them until I get Phoenix. And are player like Kylo Ren and Jedi Healer with level 6 equip (my best players) going to be worth focusing on anymore. Thank you again for taking the time to help a new guy on here. There's a lot to take in with this game!