At the moment (and this will be until IPv4 is completly converted to an independend kernel module) some switches are also used here for IPv6.
This control settings are used by IPv6 also.
This control settings are not used by IPv6. To enable ICMPv6 rate limiting (which is very recommended because of the capability of ICMPv6 storms) netfilter-v6 rules must be used.
Unknown, but probably not used by IPv6.