The 2016 MacBook Pros were introduced on Thursday
October 27, 2016. This was at the "Hello Again" event that came 2 days after the Q4 2016 Results call on Tuesday
October 25, 2016.
This meant that the results for the new Macs would appear in the following quarter's results including the crucial holiday season.
I think this year's results could be announced as late as Tuesday October 30, and if they plan to introduce Macs exclusively into the holiday quarter they could be released on Thursday November 1 making it a very late update indeed.
Apple have released Macs prior to the results call though - notably in 2013 when they made the results call on Monday October 28, 6 days after the launch date of Tuesday 22, 2013 for the MacBook Pros.
The 2015 iMacs were launched on October 13, 2015 - while the results call that year was on October 27 - a full 2 weeks later.
On that basis we could be looking at a release date as soon as Tuesday, October 16 if the results call remains fixed on October 30.
If there is to be an event rather than a sudden press release, we may start seeing invites as soon as October 9 to give tech journalists time to book their travel arrangements.
I'd say that any new configuration replacement for the MacBook Air will need a full event to maximise the push for the probable buyers of the replacement model. Although Phil might have to mention the keyboard
I read that macOS Mojave has removed support for font anti-aliasing, because it's pointless on the high-resolution screens they ship now. As I'm still on a Mini, this is one less incentive to upgrade to macOS Mojave, for me.
OTOH, it would make sense to update the low-end hardware that cannot deal with 4k displays as of now.
It makes logical sense to bury the whole 2014 Mini range rather than let one model continue afterwards as an entry level machine. The inability to drive a 4k display will become telling over the next few years.
After all, if you don't end the entire range the model technically doesn't go obsolete in 5 years.