Oh wow, you are going to love it! You regularly busk don’t you? You shall fit right in! The good news is that you don’t need a permit to busk in Edinburgh apart from during the fringe festival (source) although the best income from busking would come during the festival, so if you can acquire one for then all the better. More info In general, though, Edinburgh has so many visitors that a busker can do rather well there (particularly if you can find yourself a good spot along the royal mile).
What I will say is that it is generally a VERY cold city – very windy and frequently wet. Beautiful still, but brrrrrrrr cold! Most accomodation is in tenement buildings = high ceilings, shared entrances and stairwells, and also more chilly than not!
And not a cheap city to live in – accomodation is often costly, but if you are sharing that will help. Getting accomodation without a job is tricky – does your English friend have work?
It’s such a vibrant city though, and so full of history, I’m sure you’ll have a great time living there. I would probably suggest avoiding Rose Street, which runs parallel to Princes Street, as it is the popular place for visitors to the city wanting a wild night out. This is where many drunk stag and hen parties crawl from one pub to the next.
I take it you’ve sorted a visa for coming over?
I don’t know anyone who has visited Edinburgh and come away without falling in love with it. :-)