Em regarding your issue, it strange. Can you pass me your phpmyadmin access so that I can take a look your issue? I will need to look at if EasyBlog backend menus, the records still in the db under jos_menu table or not.
Anyway, regarding your issue, it seems like all EasyBlog backend menu item was gone I not sure how and not sure if this is caused by JomSocial or not but do you think you can re-install EasyBlog so that Joomla can re-create all the backend menu for EasyBlog?
Is your EasyBlog contain any modification to the core files? If not then you should be safe to re-install EasyBlog. No data will be remove during the re-installation and all your EasyBlog configuration will remain intact