How many tetrahedral and octahedral holes are there in a bcc unit cell?
BCC doesn't have any tetrahedral voids, however we have octahedral holes at face centres. Four adjacent corners and two closest body centres. In a homogeneous lattice the octahedral is compressed along the body-centre-atom axis. However I believe we can form a hetrogenous lattice and form a close approximation to octahedral.

We have thus $6\times1/2 = 3$ distorted octahedral voids.