list users informations who flagged an entityform with views
You're on a good track with creating the Entityform type of View. When you first created this View you chose which Entityform this is about, you can see it (change it) under Filter criteria. This view is now listing all submissions for that form. 

You have also setup a Flag "Take" that users can use on Submissions of that form. And you want to show a list of all users who flagged a submission, on the submissions page. 

When you create a fresh Entityform view you'll have only the field "Entityform: Entityform ID" and the Filter "Entityform: Entityform Type". 

If you create a Page in that view you can list all the flags for all submissions for that Entityform. You can maybe use this page as a test, to see the user info correctly listed on submission, and delete it later. 

You'll have to create a Block display to be added to submissions pages, this is what you're after. 

Here is what you have to do to your Entityform view to show info about users who flagged a submission: 


Add Relationship Flags: flag_take (or however your flag is called). Configure that Relationship to show Any user, and not Current user. This will list flags from all users who flagged it, not only the flags from the user currently looking at the page. 
Add a new Relationship Flags: User that uses the previous Relationship flag. This introduces info about users who flagged the submission with "take" to be available in this Views. 
To actually display the user info Add a new Field User: Name and set it to use the Relationship Flag user. This will show the name of the user who flagged the submission. To show other user info add different user fields and make them use the Relationship Flag user (otherwise you'll show info for the user who submitted the form, and not the one who flagged the submission).
Add a new Contextual filter Entityform: Entityform ID and configure it so that 

When the filter value is NOT available:
Provide default value
Type: Raw value from URL
Path component: 2  

When the filter value IS available or a default is provided:
Specify validation criteria
** - Basic validation - **
Hide view (or whatever makes sense to you)  

And set that Contextual filter to This block (override) because it doesn't make sense to have it on a page display, for example.   
Save the view and place the block in a region you want, you can specify the path where to show the block, like you mention in your question, this is good for performance. The Contextual filter that will make sure to only list results relevant to the particular entityform submission. 


If you need to check the Block while working on it in Views enter an ID number of one submission that got flagged, to preview the result.