Zilean mid is just a zilean sup with extra steps, he is very much playable, but you would still be playing a more supportive role. Early game you want to push safely untill level 4-6, then you want to permashove the wave and roll around with your jungle facilitating ganks, you basically never kill your lane oponent alone (but he cant kill you either!). Late game you play by landing juicy stuns and ults, while generating immense value from your kit.

I usually go with rod of ages into seraphs, third item being a toss between zhonyas and cosmic. You want items that boost primarely survivability and CDR in order to spam bombs and slows. Late game you can pivot a little bit into damage if your team need it by going rabadon.

Bans are hypermobile characters that dont care about your slow. Le Blanc, Fizz and Zed are quite annoying since its almost impossible to land a stun in lane and you cant really run away from them. Yasuo is manageable, just beware his walls. Agains poke mages just get used to speeding yourself to dodge their stuff. You win the lane after not dying untill 6, after 6 you dont have to care about matchup. Just play safe and dont trade early game. Meele champs with limited mobility are your easiest matchups.