PLL bandwidth is defined as the 3 dB frequency of reference phase modulation at which the PLL will begin to lose lock.  Don't confuse it will the PLL frequency (VCO or natural frequency).

The PLL bandwidth is set by your loop filter not your VCO.  Although it is related to the loop's natural frequency it is primarily set by your damping factor.

The BW you should be worried about for the linear regulator is the closed-loop BW.  The PLL rejects VCO noise up the the closed-loop bandwidth (transfer function from VCO to output is high pass).