Meta Box

That's a good idea. The Admin Columns extension is displaying the content in the column only. It hasn't the search feature yet.

Can you clarify the "current custom post type"? What is the "current" here?

From your code above, the variable is always set by the if-else statement, so maybe the error is for somewhere else.

If you want to run the code only in the edit screen, you can add condition for the meta boxes, like is_admin(). But in that case the rwmb_meta function won't work properly in the frontend. See this for more details.

I've tested your code and it works just fine: http://prntscr.com/e6t5gi

Did you add some conditions before assigning value to $content? The error says "Undefined variable: content", so it must be not initialized somewhere.

This is the list of supported conditions for Include Exclude extension. But if you use it for user profile (with User Meta extension), then you can use only "user_role" and "user_id".

If you want to show/hide fields for a certain ID/groups, you should use the Conditional Logic extension.

See this for the difference between Include/Exclude and Conditional Logic.

Regarding the 2nd question about MB Admin Columns: currently it works only for posts, pages and custom post types.

You can define the order of your meta boxes only. Doing that by organizing the PHP code.

It's impossible to change the order of other sections in the user profile page, because they's hardcoded by WordPress or other plugins.

If you want the callback print the content, you can try output buffering, like this:

function hello() {
     ob_start();
     echo 'Your content';
     return ob_get_clean();
}

This makes the logic of the plugin consistent ('std' vs 'callback').

Hi, I've just updated the Include Exclude extension to support "user_role" and "user_id" rules. Please try this.

Hi, I will work on the Include Exclude extension for that. Currently, it has "user_role" rule (include/exclude meta boxes for a certain user role), but hasn't worked with MB User Meta yet.