Add existing user to Registration

I have successfully setup a rule to create a new user based on the values entered in the registration form and assign their newly created account to the registration, though I can't seem to figure out how to add existing users to the registration if they match what the user entered into the email address.

Here is the create and assign rule. There are some extra fields here because I added the same fields to the User Account that exist in the Registration form. This way, I can pre-populate the form later if someone adds their email in again using an autocomplete entity reference field (which I am having some other issues with but that's a different post): (If you want to use this, and do not user Commerce, remove the commerce sections before you import)

{ "rules_create_user_account_from_registration_form" : {
    "LABEL" : "Create User Account from Registration form",
    "PLUGIN" : "reaction rule",
    "WEIGHT" : "9",
    "OWNER" : "rules",
    "REQUIRES" : [
      "rules",
      "commerce",
      "commerce_registration",
      "registration",
      "commerce_checkout"
    ],
    "ON" : { "registration_insert" : [], "commerce_checkout_complete" : [] },
    "IF" : [
      { "NOT entity_exists" : { "type" : "user", "property" : "mail", "value" : "[registration:mail]" } }
    ],
    "DO" : [
      { "entity_create" : {
          "USING" : {
            "type" : "user",
            "param_field_first_name" : "[registration:field-first-name]",
            "param_field_last_name" : "[registration:field-last-name]",
            "param_field_home_street_address" : "[registration:field-home-street-address]",
            "param_field_home_city" : "[registration:field-home-city]",
            "param_field_home_state" : "[registration:field-home-state]",
            "param_name" : "[registration:field-first-name] [registration:field-last-name]",
            "param_mail" : "[registration:mail]"
          },
          "PROVIDE" : { "entity_created" : { "entity_created" : "Created User" } }
        }
      },
      { "entity_save" : { "data" : [ "entity-created" ], "immediate" : "1" } },
      { "user_unblock" : { "account" : [ "entity-created" ] } },
      { "data_set" : { "data" : [ "registration:user" ], "value" : [ "entity-created" ] } },
      { "commerce_registration_set_state" : {
          "commerce_order" : [ "site:current-cart-order" ],
          "registration_state" : "complete"
        }
      },
      { "entity_save" : { "data" : [ "registration" ], "immediate" : "1" } }
    ]
  }
}

And here is what I am doing for the Add Existing Users, but can't get it to work even though I have added some messages to see if it assigns it and it "does".

{ "rules_add_existing_user_to_registration" : {
    "LABEL" : "Add Existing User to Registration",
    "PLUGIN" : "reaction rule",
    "OWNER" : "rules",
    "REQUIRES" : [ "commerce", "rules", "registration" ],
    "ON" : { "registration_insert" : [] },
    "IF" : [
      { "entity_exists" : {
          "type" : "user",
          "property" : "mail",
          "value" : [ "registration:anon-mail" ]
        }
      }
    ],
    "DO" : [
      { "entity_query" : {
          "USING" : {
            "type" : "user",
            "property" : "mail",
            "value" : [ "registration:anon-mail" ],
            "limit" : "1"
          },
          "PROVIDE" : { "entity_fetched" : { "entity_fetched" : "Fetched User" } }
        }
      },
      { "data_set" : { "data" : [ "registration:user" ], "value" : [ "entity-fetched:0" ] } },
      { "entity_save" : { "data" : [ "registration" ], "immediate" : "1" } },
      { "drupal_message" : { "message" : "Entity Fetched 0 [entity-fetched:0]\r\nshould of been added to \r\nRegistration User [registration:user]\r\nsince it was found.. though it\u0027s not being added. " } }
    ]
  }
}

Has anyone else managed to do this yet?