Help with roles

Ok so now that I'm kinda forced to main 2 positions (don't argue with that it will bother me if I have to change roles in the team builder)

I have decided to primary adc. I like it lots.

However, what I'm doing right now is using jungle as a secondary because I really like some Junglers (Kha'Zix, Elise, Poppy, etc)

The problem is that jungle just seems so different from adc.

So my question is: what role would be the best secondary for adc?

Other slightly related question: if you pick support as a secondary, will you get it every time?

Thank you.