Geia sou Konstantinos
I tried to recreate this topology in the lab and confirmed that the hub automatically becomes an OSPF neighbor with each spoke. However, the two spokes do not become neighbors. All communication between the spokes is routed via the hub. This is because, at layer 2, each spoke is directly connected with the hub via the DLCIs. There is no direct communication between spokes even though broadcast network type has been used.
I hope this has been helpful!
Laz