You want to communicate? Every productivity solution has some chat, which can extend in seconds to a multi-user chat, to a call or video call (Hangouts, Office365). But yeah you can also use Slack, Hipchat or whatever, no rocket science for a decade. You want a feed of your coworkers? Why? You want to follow coworkers? Why? You have Facebook already.
Email, messaging, video calls, an office with collaborating features and a task/ticket management solution. THAT'S IT, you do not need more. Depending on the industry and profession some more and specialized stuff might be required (such as CRM, SFA).
I am wondering how the Facebook London remote team got the approval for this nonsense from Zuckerberg.