That's correct. 
The IPv6 parts are disabled in sysctl.
Any leftovers are removed by changing the respective config files.
Like for example with the ssh service and the nginx services.
The file lighttpd.conf has this line:
include_shell "/usr/share/lighttpd/use-ipv6.pl " + server.port
This line was commented out during the debug run... 
If I leave this line active and do ss -tulpn | grep 80, it shows:
tcp LISTEN 0 1024 [::]:80 [::]:* users:(("lighttpd",pid=57231,fd=4))
Among a few other lines already in the debug file. 