The sleep feature on newer chips allows you to play ORIGINALS online.
Backups, once patched, work online without disabling the chip.
You only need to complete the registration if you want to use games that require access to $ony Central. Most games do not require this so I wouldn't worry too much about registration at this time.
You can only play PAL games online on a PAL console, unless you change the machine ID. As mentioned this cannot be discussed here so your best bet would be to google for more information.
Now will a PAL console work online from Pakistan? I have no idea. I thought I'd read somewhere that $ony block IP ranges outside of the correct region but this may not be true.