On the point of adding the interfaces to the bond, you don't even need to do a cpstop, I do think however that you will need to set vsx off before changing anything to your interface settings, make the changes and then set vsx on.
From the VSX perspective make sure the added interfaces are not in your VSX cluster interface list, if so remove them from the list before you start.
So your steps again:
check interfaces in VSX Cluster object
ssh to management
vsx_util vsls - move all to member A
SSH to member B
set vsx off
add bonding group 0 interface eth1-03
add bonding group 0 interface eth1-04
add bonding group 0 interface eth2-03
add bonding group 0 interface eth2-04
set vsx on
save config
go to management
vsx_util vsls - move all to member B
SSH to member A
set vsx off
add bonding group 0 interface eth1-03
add bonding group 0 interface eth1-04
add bonding group 0 interface eth2-03
add bonding group 0 interface eth2-04
set vsx on
save config
go to management
vsx_util vsls - distribute load
all done.
Regards, Maarten