This looks like Internet down at that time, as every repo gave a 404 error.
why the downloading speed is too slow, it takes so much time to download. Is there a problem with server, when I downloads videos or other files from net it downloads fast but this taking very long time.
Software & Updates and look at the Download From option - What is your server set to?
It sounds like packet loss, to me... Odd that only the updates are affected, though.
It's the same exact protocol in the terminal as it is in the GUI app or browser.
There are essentially 'placeholders' for upcoming modules in the kernel. Usually, updating the kernel (When it is released) resolves that.
Yes, that upgrade looks complete.