1 - Ah, you caught a pretty good bug. I think I'm checking "less than" where I should be checking "less than or equal to." It should be class 1, but borderline things like that can go either way. I've updated the template - copying & pasting cell B2 should be the only change you'd need to make.
2 - Hull points is your vital structural integrity; it would be your health points if your ship was a flesh-and-blood units. So it doesn't really come from anywhere; it's inherent to your ship's class. (I'm not married to this idea now that I think about it, but that's maybe something to discuss after we meet later this month.)
I think that might've been more of a formatting problem as I rearranged the sheet - C8 calculates what this value should be (it's equal to baseline power) and B8 is just a free space to write in a current value (assuming you would be using this sheet during actual play.)
3 - The rule we tested out last we met late December was "you can only spend X power on shields and armor" where X = your class. So a class 6 could spend 6 power on shields and 6 on armor at maximum. The other rule we added was that armor was more effective on larger ships - Small ships get 2 armor points per power, mediums get 3, and larges get 4. I'll write those up in the official rules shortly; hopefully I'll also manage to get together a quick reference sheet/sheets for actual gametime organized as well so we don't have to have the site up while we play.