I don't use solaris, but I've read that if RBAC is used to turn root into a role, then a user cannot su unless they are allowed to assume the root role.
Please use code tags when posting output of the commands. To set static IP address on net0, try this:
netadm enable -p ncp defaultfixed
ipadm delete-ip net0
ipadm create-ip net0
ipadm create-addr...