1: Can't download them.
File/Download as ... ?
2: Although one is for the MEGA, what is the first one for? It just says ARDUINO. Is that the UNO, Ether10, Eleven?
It's pretty old. There was the Arduino, and there was the Mega. At the time. Diecimilla, I guess. Pretty much all the 8/168/328 designs use the same "pin names" even when they have different physical layouts (Nano, etc.)
4: It doesn't show the pins with "built in pull up resistors".
That would be "all of them." I mentioned that earlier...
I am also not sure the importance of the PCINT and PCMSK columns.
Just because they're features you're not familiar with (Pin Change Interrupts), doesn't mean that they're not useful to have documented.
Those two pages also overdo the SPI and I2C bus names. They are listed in two columns for no good reason I can see.
Bottom-up vs top-down documentation. The "special features" column documents (comments) on most of the features on all of the pins. The SPI and I2C columns are for when "I need I2C, Where is it!"
What I want is a sheet which the person can print out/off at home for "that" project.
So... It's a shared google-doc spreadsheet. If you have a google account, you can copy it and rsort/add/delete whatever columns you want (including the addition of a blank column for you to fill in my hand on a printed copy, if you want.) You should also be able to do that with your own spreadsheet SW if you download it.
No one is ever going to be able to produce a "thing" that is perfect for everyone. This sort of open source "thing" where you can modify the parts you don't like is the next best thing. (HW, SW, Docs!) I think that some of the pictures are "open source" as well.