Hi,
you should not use Instant facebook social login and JChat social login together, they could conflict and the throw the error reported.
Avatar: it's expected it's how it works. At the moment the avatar used in the social network is imported by IFBlogin module BUT NOT in the chat app. however it's a planned feature in future release of JChat
If you have IFBLogin just use it without doubling the social login feature in Jchat too.
If you still get "user informations not found and retrieved from the social network" check your Joomla and source code for any other inclusion of the Facebook SDK with different ApiKey by other extensions. This is a common issue that leads to this error.