Hi,
can i export all users and passwords and other data ?
You can export only Joomla core and Easy Profile informations (not information from the other plugins). When you export the password then the system will export only the hash (not clear password), anyway you can re-import the hash of password to allow user to not change it.
can i import them after restore some backup before without request users new password ?
Yes, with the hash of the password
can i edit style or them for social network like font size, colors and mobile view?
Yes, but there is not a tool to do this, you need to add a custom style (CSS) code to your template manually.
users well be registered via Facebook the data of them like email and passwords will save in database or not
When a guest register an account via facebook then the email address will be the same of facebook and the password will be generated (no way to keep/retrieve facebook password, this is a facebook security thing). If a email is already registered then the system will ask you to make a login with Joomla credentials to link the account or specify another email address.
can i export them and import after restore backups with out request new passwords ?
The account will be imported like all other Joomla account.