Which is correct.
1. Whose are these shoes?
2. Whose shoes are these?
3. Who are these shoes for?

Question

Answer

If you want to ask who owns the shoes (who do they belong to), you could use either of the first two sentences. Most people would use the second sentence, though.  The third sentence is grammatically correct, but it is not asking who the shoes belong to.  Instead it is asking who the shoes were purchased for or who they are going to be given to (who is going to receive the shoes).

Answer

All 3 are correct.