> Is it the case that the system can't be started on a machine with the IPv6 stack disabled?
It can be started, but it can't be initialized using UI. I didn't test initialization using CLI for this particular case, but most likely the behavior will be the same.
After discussion I reproduced it on ubuntu 16.04 vagrant machine using the following steps:
1) Disable ipv6 in grub configuration in /etc/default/grub:
2) sudo update-grub
3) restart the machine
4) install couchbase package
5) try to initialize the node using UI (ipv6 checkbox is unchecked)
6) after pressing "Save and Finish" node doesn't respond