Vettel had a scrappy FP1 which is probably why he slower in FP1 but a bit quicker in FP2. Just remember that last year Kimi out qualified Vettel over the course of the season so it's not because he doesn't have it in him. Kimi himself has said he hasn't been able to get his car set up right for whatever reason so who knows what could happen during qualifying.
Vandoorne already got a grid penalty for using too many engines over the course of the season. He is on his fifth turbo and MGU-H.