Typically the meeting invites go out as late as possible the night before - so expect invites at 11pm or later
It really depends on the individual manager and how many people they have to notify. They usually start going out 60-90 min after the earnings call ends.
I knew something was up in '16 when our manager sent out a mass team message at lunch time advising everyone to watch the earnings call that afternoon. He bolted out of his office 15 min before the earnings call started. An hour after the earnings call, people on the team were commenting in Jabber (pre-Webex) that they'd received meeting requests for the next morning. We pretty much knew then who was a goner.
The night before which weekday?
It's the night of the earnings call, so you're notified first thing the next morning. Cisco has moved to the "rip the bandaid off" notification model instead of announcing the LR ahead of time, telling us how many, when the notification period will be, and what the package looks like. And they call this new model "more transparent".