Complete configuration of Octavia requires the creation of resources in the overcloud. This requires host configuration steps and openstack cloud operations on the overcloud glance, neutron and nova services. Running ansible from a mistral workflow seems to be a workable solution as it has the required integration with heat and allows host level commands to be run in a deterministic intuitive manner.
Is this bug still on track for beta/ga?
Yes, RFE should be used for Octavia Tech Preview in OSP 12 hopefully
Pushed to OSP13, covered by bug 1506644