The Carabao Cup Rd 3 games are due to be played either w/c 15th or w/c 22nd. To allow for teams in Europe to play in a week where they are free. So either is an option but as you say with Exeter already scheduled it may well be w/c 22nd.
There aren't that many midweek League games coming up so Burton will fit in somewhere but of course we will have Oct and Nov international breaks as well.
Going to be lots going on.