They most definitely can read triple layer discs as they are commonly used for 4K Blu-rays. And when a drive can read TL-Blurays it most likely also can read QL-Blu-rays just fine. However, those are rare so I would suspect a 2x TL release.
A single Quad layer Bluray could fit the entire game, but not a ton of PC users have an optical drive, much less a Bluray capable one. A microSD card or USB drive might be more viable these days. A 128GB costs less than $10. When you want to stick to DVDs you would need either 27 (DVD-5), 15 (DVD-9) or 8 (DVD-18). Multi-DVD releases are definitely a thing. Star Wars Battlefront comes on 4 discs. I suspect they would opt for a DVD-9 release as this allows you to print artwork on one of the sites and you likely need a few extra discs as you cannot use all of the storage for data. So we talk about a 16-18 disc release. ~22mm (7/8 inch) of DVD goodness.
It actually does. Blurays go up to 128GB and the game needs 125GB.
Yes but also expect to pay more. IIRC they will honor google's pricing for the first year but afterward you more likely than not have to pay more. And you might lose some features you use.
NZ and USA are the only countries in the world to allow it.
No, a ton of others also allow it but there might be more more (or fewer) restrictions. But yes, advertising pharma products is pretty weird. Your doctor should proscribe your meds and you should not ask for something specific because an ad told you so. And many of those proscription free cold medicines are not really necessary or effective anyway.
Are you also using Powerline? This can cause all kinds of wanky issues.