The CPU is listed as 4x dual-core AMD64 "Bulldozer": Don't believe it, 4-6 cores in total (2-3 bulldozer units)
GPU is listed as an AMD R10xx: probably right as the GPU is the single most important part to get right in a dev kit
160 GB HDD: Absolutely, and I would not be suprised to see much larger drives, as well as an SSD option down the road
Blu-ray drive: maybe, maybe not. I know there was talk of 'download only' for games, but if they want it to be a multimedia center then it needs a blu-ray player.
four USB 3.0 ports: possible, more likely to see some cost cutting with 4 USB2 for controllers, and 2 USB3 for external HDD option (my origonal thought was they would have a small SSD for the OS and user files, and then force users to get an external USB3 drive to store games)
two Ethernet ports: Why would they do this on the final build? One gigabit port is already 1 more than what will be used by most users. Give it an ethernet and wireless N, and call it a day.
HDMI and optical output: Absolutely will happen, likely firmware upgradeable HDMI to support future 4K and Ethernet over HDMI technologies.
2.0, 5.1 and 7.1 audio channels: Absolutely will happen. Audio is cheap and easy tech to integrate, and the PS3 already has this, so why would they take a step backwards?
"The PlayStation 4 will also supposedly offer multi-user simultaneous logins, meaning the console will allow more than one person to be logged into the same system at the same time. This is done by linking controllers to user accounts, thus when a second player activates a controller, he/she will be asked to log into their account."
The problem with this is that I would then be expected to carry my controller to my friend's house, or expect people to be able to tell each of their identical black playstation controllers apart... I like the general idea behind it as it allows for trophy tracking when you are away, but it also may allow developers to say "you cannot play as the 2nd player on this game until you pay a $5 log-in fee, or purchase rights to the full game" kind of thing. That would be terrible.