Can't imagine that will go down too well with Aston.
From Toyota's point of view the more of that platform they produce, the better the economies of scale and the lower the price the IQ could be sold at. That said, I would have thought there would be enough internal customers to make it cheaper anyway (Lexus, Subaru etc etc etc) if they wanted to do that.
The bigger question is, are BMW looking at making a "Proper" Mini; a car that has a small foot print and excellent interior space?
It's all about the twisties....