Can I use more than one Window on an FFT?
That makes little sense; the FFT (which is just an implementation of the DFT) is a linear operation; summing/weightedly averaging the same signal windowed with different windows is mathematically identical to just windowing with the summed/weightedly averaged window to begin with. It's literally the same.
So, what you really want is to design / choose a window that's appropriate for your use case instead!