3 Questions

You can install JFBConnect on all of your websites and do not need to purchase another license. If you're encountering errors with K2 Likes/comments, it would not be because of this.

I am trying to set up the K2 Comments and K2 Likes on the new site but it is not working, is that because of the license or it could be something else, let me know please if you need access to the site back end.

Please verify that you have enabled the JFBCContent plugin. If possible, please provide a specific URL where it's not working and take a screenshot of the settings in the backend for how you've set up the like/comments. Any more specific details would be helpful - such as the buttons are not present, or are present but nothing happens when clicked on, etc.

Am I able to disable the whole login/authentication module and use my normal Joomla login capability only?

If you want to continue to use the SCLogin module but don't want the social buttons to show up there, there is an option in the latest version of SCLogin where you can disable those buttons. Look in the SCLogin > Social Button Settings tab to find that option. If this isn't what you're referring to, please let me know.

-Melissa