Yes you can use your Flying Club miles on partner airlines such as Bmi. You wont be flying Upper Class, you can redeem your miles for a flight WITH Bmi, utilising their Economy or Business product.
I am not sure how the YVR flight works in terms of redemption as it is a codeshare though i would presume you could do it. Unless a more learned V-Flyer comes along shortly, your best bet would be to call Flying Club and see what they can advise.
Partner redemption rates are for a return journey, thus a one-way redemption would cost you the same amount of miles, silly really. adjonline; i think you would be better off looking at a SFO/LAX-LHR routing with VS, or fly the MAN-MCO segment with the partner airline.
Thanks,
Sarah