Who should I main per lane?
Top: Darius or garen? Mid: Ahri or annie Adc: Jinx or kalista or vayne Support: Thresh, blitz, braum, or naut Jungle: I dont jungle so not a lane
Top: Darius or garen? Mid: Ahri or annie Adc: Jinx or kalista or vayne Support: Thresh, blitz, braum, or naut Jungle: I dont jungle so not a lane
Naut jinx annie and garen are easier then the others you mentioned and all very effective, i doubt you will ever get darius in ranked he is broken and permabanned
None of them. They're all unfair and/or extremely overused champions. I pick the ones I like the most, and I stomp on my lane opponent 85% of the time.
I probably wouldn't main either
or
as they are currently at an insane ban rate and you wouldn't even be able to play them.
I would choose the champions with the simplest mechanics, as less things could go wrong.
Mid:
ADC:
Support: 
vaynes mechanics are much more difficult to use well than jinx's
yeah, you're right.
Asuming you are on soloque I would suggest Garen, Ahri, Jinx and probably Thresh. If you are the one that plays more with friends I would go Vayne, Darius, Annie and Naut... they are more fun to play in my opinion
If you want to climb into gold instantly just spam 
If I have a friend supporting me I'll go kalista, otherwise jinx. Thresh and blitz can practically carry a game regardless of how good their adc is. Can't deny the simplicity and damage of annie. Garen takes a little bit more know how about your damages to stay relevant but only a little.
How good are your mechanics?
If they are not great these should be your choices:

Otherwise whoever you want. All are good choices.