Database project
If it should be the sort of thing that belongs on this page, you could add a section in 'General' on the Conlang Database Project, currently being planned and organised. The main location to link to is probably our planning document, it has links to everything else: https://docs.google.com/document/d/1y5QhCZpn3XcaosbP3wAEtoNGluLHHLzvateNZNAI6Ek/. We would like to attract more people to take part in making decisions and compiling the database. Assuming it happens it will be a subdomain of the LCS website, like CALS which has its own entry here.
TBH there are quite a few more conlang Facebook groups than the one named, it's up to you how many you're prepared to include in 'Social Media' but these are the ones I know:
https://www.facebook.com/groups/243612669152055
https://www.facebook.com/groups/ConlangIdeas
https://www.facebook.com/groups/Conlang/
https://www.facebook.com/groups/conlangsforfree/
https://www.facebook.com/groups/constructedlanguages
https://www.facebook.com/groups/CrazyConlangIdeas
https://www.facebook.com/groups/116059865455376
https://www.facebook.com/groups/Linguistics.and.conlangs/
https://www.facebook.com/groups/conlangsesp/
https://www.facebook.com/groups/313795458742430
https://www.facebook.com/groups/romlangs