MOSFET: Purpose of a Gate Resistor
#1 isn't exactly the goal. It would be to limit rise and fall times to reduce EMI.
#2 is to dampen ringing on both rise and fall with the driver. But in addition, to dampening ringing between parallel MOSFETs which means one per MOSFET since a ringing loop exists between them. Sharing a gate resistor won't prevent parallel MOSFETs ringing amongst themselves.