Can I book trips & reserve seats for all Eurail passes before sending passes to each device

Hi there, I’ve tried navigating other peoples Q & A’s, but not sure about getting all the right answers, here goes”

I have purchased 5 x Eurail global passes for my family members, who are travelling together initially, but later splitting up and travelling our own ways.

Can i prebook trips and reserve seats collectively for all passes, before allocating passes to each persons device……   & can i do this on my computer, or does this process only work through the app….

Or do I need to allocate passes to each device first & then do we all have to book trips & seat reservations seperately - hoping that we can still book at the same time & ensure we have seats together??

I assume this process of booking trips and seat reservations, does not mean we have to ‘activate our passes yet?’ Assuming we only have to activate our pass on the day we actually travel (have booked to travel)

cheers