Since the IPv6 layer settings already take care of IP addresses that are present in the ICMPv6 layer (like for ICMP redirects, and tons of IMCPv6 TLV options), this section does not have any settings for this. Also, TraceWrangler will process quoted IPv6 packets (for Destination Unreachable etc.) just as another IPv6 layer, so the IPv6 parser will kick in again. This means that also quoted packets will be sanitized, of course.
Remove DNS Server FQDNs: some options may carry FQDNs, e.g for DNS domains in more advanced Router Advertisements. With this setting, they will be sanitized by replacing all characters with an "x". E.g. a domain like "test.local" would end up as "xxxx.xxxxx".
Remove Ping payload: if you want to remove the ping payload, check this option. Otherwise it is kept, even if you selected "Remove unknown payload" in the general section. Well, it isn't unknown anyway, since TraceWrangler knows what it is, right?
Recalculate CRC: this works just like the IPv4 setting. Since sanitization may lead to a modified ICMP layer, the CRC needs to be recalculated. But in case you want to keep bad checksums bad, TraceWrangler do it the same way as for IPv4.