Unfortunately the setup for Encounters uses image buttons and the theme is only coded for the existing group that is available. Celestial Reloaded, on the other hand, uses a font for the icons which makes it easier to add more. I could add the ones you are mentioning, but this would of course be billable time. If you need this done, feel free to contact me with what additional social groups you want added.
The only other option would be to use a plugin for social networking that contains the ones you want.