1) No start command. Check /etc/init.d/rcS: it simply runs "daemon start" where "daemon" is given each value in RUN_DAEMONS in turn.
2) Both ways are run by root. If you really need another user, you could put the following in local.sh:
su -c "tor -d &" - username &
3) Maybe does tord automatically run the service as another user? You can check, after starting it, who is the owner by:
ps | grep tor