A detailed theoretical understanding and experimental characterization of magnetic nanoelectromechanical devices is crucial for future technological applications. Here, we investigate the transport characteristics of a nanoelectromechanical spin-valve device, which is coupled to two magnetically polarized electrodes with arbitrary polarization directions and strengths. For a weak polarization, the electron transport is dominated by electron shuttling at a low damping. As the polarization increases, the electronic current decreases monotonically, until the system reaches a renormalized tunneling regime. Intriguingly, in between these two limiting regimes, the current noise can exhibit a non-monotonic turnover as a function of the polarization, and is vastly enhanced due to the competition of the dynamical spin blockade and the bistable mechanical behavior. As the polarization increases, the bistable mechanism is quickly destroyed, resulting in a transition from a local noise maximum into a minimum at the antiparallel magnetization configurations. These findings may shed light on potential ways to achieve polarization-controlled current and noise modu- lation in NEMS spin-valve systems.