Agree student visa seems unlikely and very expensive.
Also wondering what the Sisters status is. Sort of sounds like she is in Spain?
There was a forum that sort of specialised in waivers but that closed down a long time ago.
i can think of quite a few Lawyers that are well versed in waivers, just wondering what the issue was that the Lawyers you consulted with raised.
Biggie issue that comes to mind is the QR is a recently arrived LPR.