I don't think so - static ips on both ends is ideal. pppoe should take effect at L2, and IPSec at L3, so their should not be any issues. I believe the tunnel will have a slightly lower MTU than most, due to the PPPOE overhead, but that should not present any problems
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...