So: with DHCPv6 you do get an IPv6 address on your Linux? That would be nice. Run the commands I gave you: test-ipv6, mtr, ip
Furthermore: a DNS with only a IPv4 address will also resolve IPv6 addresses (see example below), so no need there.
sander@flappie:~$ host www.facebook.com 188.8.131.52
Using domain server:
www.facebook.com is an alias for star.c10r.facebook.com.
star.c10r.facebook.com has address 184.108.40.206
star.c10r.facebook.com has IPv6 address 2a03:2880:10:8f07:face:b00c:0:1
star.c10r.facebook.com mail is handled by 10 msgin.t.facebook.com.