MM, glad I could help - well, with three out of the four! You haven't given the clues for 7, 9 and 10 - not everyone will still have their copy to hand. (And people who don't do EV sometimes enjoy seeing and helping with it, so I think it's a good idea anyway.)
Your Serges is correct, your Nyssae isn't! (Nyases).
6 D. Havana, smoke (noun) AA = drivers and Van = Lead. (H is the crossing letter, not clued)
You'll maybe get Unfinished... once you correct the 'flappers'.
Hi mm,
your flappers should be nyases which should help with 10a/2, serges is correct. 6d think of a name/type of cigar, wordplay is a 3 letter lead in the usual 2 letter abbreviation for drivers.