you should leave as your first preference whichever one you want to do most, which i'm guessing is international and global. and you should enrol in UTS in case you don't get an offer from USyd, you can always withdraw later on
when i was at UTS, most of my classes were at broadway, but one of my tutes was at haymarket.
and back to back classes is fine, there are usually 10minute gaps in between, so there's plenty of time to move around
Maybe you should leave the uni advice to people who have actually been to uni? Tutes are more important than lectures, and there's no reason you shouldn't have back to back classes, heaps of people do
I think they can legally do that if you're casual, but they're not supposed to.
And was the manager your restaurant manager? If not then talk to the restaurant manager
For my store, there's usually about 5-10 people for orientation, although other stores probably do less.
And its hard to say when orientation will be, depends on the store