How to use views and LDAP query to get a list of names in a webform?
If you have a valid ldap query with names and emails your basically there with Views and LDAP.

You want to make a custom webform component in a module using PHP code. You can use views_get_results to get the results of the LDAP view as an array.

Then just build a webform component as you would a Forms API select widget with your values.

You then tell the webform to use your component in the UI.