there isn't a chance in hell of any sane FI authorising that one.
The beach landing wouldn't worry me if you had done one before its the mountain flying and water crossing which would I wouldn't be able to justify as acceptable risk to send a solo student on. Especially as there are so many safer options available.
What the student decides to do post PPL issue is up to them.
Anyway you have some better options as well which won't require all the moons in the solar system to align for favourable weather. They will also teach you more having to cross various bits of airspace and talk to different ATC.
To barra you will just be on Scottish Info once outside PIK zone.