Drupal Bulk Update Nodes using button
I seem to have solved my issue, i will try to elaborate for future reference and also for any one who may need this.

First, it seems i missed the "Bulk operations settings" section as it was collapsed by default. But one of the options under it is "Display operations as" which provides two choices (1) Dropdown selectbox with Submit button and (2) Each action as a separate button

The second option was what i needed to get the buttons i wanted.

Then for bulk updating a custom field of my content type, i added hook_action_info() into my custom module and created a custom action that would become visible where the "Modify Entity Value" option was.