CHARACTER STRATEGIES - Captain Phasma, Kylo Ren and First Order Officer

Greetings fellow heroes!

I have just unlocked Kylo Ren after 4 days of farming him from 4C. I will keep farming him to star him up. My questions are:

1) Which abilities should i prioritize in leveling up? ( i have limited purple ability mats )

2) Should i rush him to gear 7? Or just gear up my Sid/Lumi first to 7? They are both 6 stars btw.

3) Im currently running a team of phasma(5*)(lead), sid(6*), lumi(6*), jc(4*), poe(4*)/fotp(1*). Who should I replace for Kylo?

I look forward to your advices and comments.

Thanks!