Squid can't filter https, that is because ssl, and the reason ssl interception option on squid conf, but it doen't work(cause certificate issues)
Nonsense. It sounds like you don't have it configure properly.
BTW squid can block https on non transparent proxy mode, which is silly because anyone with a brain can bypass it on non transparent mode
It never occurred to you to block 80,443 tcp on LAN?
Squid Guard block all option does what it says block everything even white listed sites, just tested it
I'm pretty sure you can and you're doing it wrong.
as it read block then allow and not allow then block, or there's a option to change which direction it get first(block/allow; allow/block)
Sorry, what? I don't understand what you're trying to say.
Watch this:
https://www.youtube.com/watch?v=xm_wEezrWf4