Maybe we can address their concerns with our platform Open Social (getopensocial.com) as they use Drupal for most of their platforms already. I think we can get some data our of Workkplace trough https://developers.facebook.com/docs/workplace/reference/gra... - would be an interesting case for a migration tool..!
We are happy to have the backing of orgs as the UN and the European Commission. Goal is to go fully decoupled using React and GraphQL next year.