What to name field collection theme file? There are several articles here that address theming field collections but none that specifically cover the naming conventions required to actually get them recognized by Drupal.

field--field-field-collection-name.tpl.php does not work for me. Perhaps because I am theming the edit page of my field collection, but field--field-collection-name--edit.tpl.php doesn't work either. I have tried every permeation and order of names I can think of with no success.

Surely there is a way to theme a page whose URL is domain-name/field-collection/field-field-collection-name/*/edit.

Any help?
Theme hook suggestions typically work off of content type (or in this case bundle type), field name, or other variables. URL is not one of the defaults.

However you can create a custom template suggestion and use the URL to create that suggestion. If you want to theme the edit page you'll want to make sure you're putting the template and template suggestion in the administration theme.

Here's a good page on theming suggestions:
https://drupal.org/node/1089656