I think the reason it’s 3 Hours is that not a lot of groups are out raiding/hunting for more than 2 hours at a time. Obviously for someone who mainly plays solo (like myself) and for someone who might have work or exams I see how frustrating it must be to not be able to enjoy this event in its entirety. Personally I feel like it should be the whole day, but a lot of people disagree.
It is 10am to 1pm on a Saturday. So I guess Niantic expect less people to be working
I’m just guessing the weather will be terrible and then I will not be able to go down to my local park, because it will be closed for the weather
I agree with pretty much everything you said except one thing. If I’m right, I don’t think you can have a shiny hat pichu since the hat pikachu lines have never been available shiny.