November 17th would be a good date.
Regarding the lineup, I don't think Forza Motorsport 8 will make 2020, they've been busy overhauling the engine and only just started development IIRC, I could see Playground coming to the 'rescue' with Forza Horizon 5 though, but they'd be using the old Forzatech engine, not that I think that matters, I've never looked at Forza Horizon and thought it needs a new engine.
Everwild has no chance of releasing in 2020 imo as it's still in pre-production with a team of 50, I see that releasing sometime in 2022. Gears Tactics I think will be in the later half of 2020 so that sounds reasonable, Psychonauts 2 is a mystery, there's no hard release date and Microsoft has announced most it's XGS dates for early 2020 so I could see that releasing in late 2020. I also don't see Flight Sim releasing on Xbox until like 6+ months after the PC release.
I'm curious about how Microsoft will handle the launch lineup, with Gamepass it makes more sense to spread your releases out, will they have a big launch lineup that will likely get overshadowed by Halo Infinite anyway, or will they spread the releases out, maybe 1-2 smaller titles to sit alongside Infinite and bigger titles in the months afterwards.
I also think it's harder to predict as I believe XGP will pick up some slack as their internal studios won't be ready; Hopefully we get another Killer Instinct though.
Lineup: Halo Infinite, Forza Horizon 5, Killer Instinct, New XGP IP?
I'm guessing with your launch lineup you are just mentioning first-party games? It is almost guaranteed the annual sports titles will also be launch titles, as well as CoD 2020.