I'll go for Draven he can burst Vayne down so quickly plus he has some mobility and thats good !
I'll go with Vi cause she is a great engadger she can be played full ad, tanky ad and still do a lot of damage, she can burst zed down so fast.
For me Leona is the best support , i like these tanky engadgers like braum but she has a lot of CC and she was awesome with Graves but now i m not...