No problem. It keeps track of what OnePass account is used to book the ticket completely separately from what frequent flyer number (or even what name) is on the ticket.

I have an old OnePass account I use almost exclusively for booking and keeping track of my and my family's reservations at continental.com.

I've booked three itineraries since signing up for the Travel Club that have been completed (with two more itins booked but not yet flown): one was for me and two were for family members. All of them were booked with NW WP#s, and all three posted $5 credits to my account a few days after they were flown.

It seems as long as you're logged into a Travel Club-enabled OnePass number when you book the ticket, it doesn't matter who it's for or what FF# the passenger uses--you get the $5 credit after they fly.