Jump out on that limb! We love wild speculation! I'm gonna go point by point not because I think you're wrong, but just to laser in some details
You (and I) have no idea how many developer kits are out in the wild. Yes, the noise tends to increase when there are more devkits out there, but as you point out, Nintendo "don't require a ton of 3rd party games to be there right at launch" so I'm not sure we can make hard release timing guesses from it.
Sure, Furukawa might be hedging but a denial "means yes there will be new hardware this fiscal year" is a bit much. If Furukawa
wasn't saying new hardware was included, then aren't they saying they plan to sell 15 million Switches? How do you sell 15 million Switches while releasing new hardware, which you announce before the holidays?
The Pokemon leak came out the day before the Direct, and included nothing confirmable that wasn't in the video. I think we have reason to be dubious about it
We know that hardware is in production because where else would devkits come from? That doesn't mean it's retail hardware.
Part of the problem here is that the only "modern" Nintendo launch we have good data on is the Switch, and we know the Switch was rushed out the door. This is about the time that devkit/retail production started up in 2016 for the Switch launch, but we also know that Nintendo was putting beta firmware on their hardware, because they were rushing to make March. So maybe they are targeting March again. Or maybe the last launch was rushed, and this isn't?
That's not a thing Ubisoft said. They said they were told by Nintendo that one game-per-console was the best cadence. This conversation likely happened when planning for Sparks of Hope began, early 2021 at the
latest.
Microsoft internal documents say they expect 2024, not any specific date, and the expectations seem based purely on speculation. Microsoft internal documents also said
Tears of the Kingdom would launch 2020.
I think you're right, but was it "last 3 months" out the door or "last 9 months" out the door? That's the difference between a March and a September release. Do you release
Wonder as your Holiday title, target 15 million units sold, then announce the new hardware in September?
I think it could work again! But March was forced on Nintendo when they couldn't get the Switch out the door for the intended release date of October 2016. It wasn't a considered choice by Nintendo, and I'm not sure if they'd repeat it.