I don’t think there is any template available on Adalo yet for SNS. I am not sure if there are any free templates but you can check out getstream.io and getsocial.im for your news feed API. Getstream.io seems fantastic and they have a chat API too but it is too expensive. So if getsocial.im.
Having said that, building your own activity feed on Adalo is fairly straight forward. If you grasp the concepts of collections and lists, you can do it within an hour.
I built my own ‘activity feed’ a la facebook activity feed. There’s a ‘like’ and ‘comment’ component as well specific to each feed. Users can obviously post new feed and also filter feed by different conditions.