Is there global setting or hook for setting "Allow front-end editing of entries" for all forms

As far as I know, there isn't any WordPress hook that will allow you to change the value of the checkbox. You could do this in jQuery. The following code will check the box:

jQuery('#editable').prop('checked',true)

Of course it's a little more complicated than one line of code. You have to create a script that is loaded in the WordPress admin and also test that you are on the right page just in case there's another field out there with the same ID. This will work on new forms that you are creating.

For forms already created, you can do this with SQL. The editable field is located in wp_frm_forms table. For each form you want to make editable, you have change this value to 1. A sample SQL script for a single form is:

UPDATE `wordpress`.`wp_frm_forms` SET `editable`='1' WHERE `id`='80';

For multiple forms in the same SQL statement, use:

UPDATE `wordpress`.`wp_frm_forms` SET `editable`='1' WHERE `id` IN ('80', '81', '82',);