Should I make it possessive or not

Hi,

I think I ask several question in the similar vein in the past but for the sake of personal clarity, allow me to ask one more. Would you place them possessive or not? Are there some tangible guidelines on this?

monitor attendees' participation

monitor attendees participation

the customer satisfaction with our product

the customer's satisfaction with our product

will not consider volunteers/staffs withdrawal

will not consider volunteers'/staffs' withdrawal