Waleikum Assalam Brother.
I don't know the answers to all of your questions. But I have a great experience living In UK for two and a half year.
When People decide to move to London for work, study or any other reason, they ALWAYS face some difficulties there. And after spending some time in London, 60% of the people decide to go to Scotland rather than living in London. Scotland is 8 hours away from London By driving distance. I have a great experience of Lifestyles of London, and Glasgow.
The People of London are too nice that In Pakistan I've never seen such nice people. Sorry to say.
And In Glasgow, Scotland, you will see the worst people. Most of them.
The food is too cheap in London, And too expensive in Glasgow.
The rent for living in House/Flats is cheaper in Glasgow, and in London it's much expensive than that of Glasgow.
And let me tell you, you seriously don't want to work more than the hours allowed as you will be caught in a week or Maximum a month. And you'll have to face a Penalty. That will make you go insane for sure.
Live there according to their Policies and you will have the best time of your life.
Now as far as I've seen, students going from Pakistan to study in UK can't find the jobs they really want. They can easily get Security and restaurant types of jobs, and these can make you live there easily.
Except from this, the studying is really great there. You'll find many Pakistani's where you study, and live.
Most of them speak PUNJABI only.
The environment is too good, and of course so much peaceful... Too much really... as compared to the Peacefullest place of Pakistan.
Hope you got a little help. Enjoy your trip. Good Luck