EK Build Questions

Hey I've played a couple hundred hours over a couple of Leagues and I am thinking of playing a EK build but don't really know how to go about it as it seems most the builds are around 3.0/3.1. So I have a couple of questions.

A. Is it a good league start? I haven't seen many streamers talk about it.

B. Would EK be able to complete all content?

C. Would it need a boss killing skill?
C2. If so what skill would be a good option?

D. Would you level with another skill or just use EK the whole time?

E. What would an example tree look like?

Thank you for your time my dudes.

A. Yes

B. Yes, not Uber Elder unless you have a lot of investment.

C. Maybe
C2. Vaal Blade Vortex

D. Blade Vortex or Storm Brand

E. Just a 3.5 Blade Vortex tree