If previous pillion setups are any indication, the passenger grab strap #11 gets bolted down by the bolts #14 onto the subframe and then just slips over the pillion when installed. At least that is how it is on the previous CBR1000RR and the CBR600RR. When you remove the pillion seat, the strap stays connected to the bike. You can also remove the strap completely and ride a pillion without the strap.
OP, I think all you will need for your purpose is just the pillion seat without the strap and bolts.