Upvote:2
This story would be much clearer (and your friend could get much better advice) if she'd represent herself here.
That being said, your friend has a refusal for a Tier 2 visa in her history and that is causing her problems even for just a layover. Now when already that layover caused her a fair bit of trouble, she can expect worse (including detention) when showing up and attempting to stay for a few days - as she has been told in no unclear words as it seems.
She should apply for an entry clearance which would greatly improve her standing with immigration officers in the future. How to do so is described in this post for the US - the Canadian case is likely similar. The problem with that it is likely practically impossible to get it while traveling, as passport and other documents need to be sent in.
So my advice is: