Disable See More Popup Facebook – How to Disable See More Popup on Facebook Pages

No, you cannot do this. The key part of this question is, "[The other page's] admin is not my friend and neither do I know him/her."

Notice that Facebook says, "Click the Merge duplicate Pages link. This link will only appear if you manage two Pages with similar names." Emphasis added.

The only way to merge pages is if you are the manager of both. There's nothing you can do (aside from reporting it to Facebook) about a page if you are not the manager.

You can not create a secret page on Facebook. This functionality is not available as of now. But you can unpublish you page.

Published Page is visible to the public. Unpublished Page is only visible to the people who manage the Page. Unpublishing your Page will hide it from the public, including the people who like your Page.

To unpublish your Page:

1. Click Settings at the top of your Page.
2. Click Page Visibility.
3. Click to check the box next to Unpublish Page.
4. Click Save Changes.

Your Page won't be visible to the public until you publish it again.

Note: You'll need to be an admin to unpublish your Page.