fill existing items checkboxes, neverRemove

 1. I have an editor that already has 100 items in it. I am adding a neverRemove checkbox to these items. I am selecting them to be checked as default. However, existing item checkboxes are blank. how can I fill them?

 2. I am also adding publishDate and removeDate. I don't need anything to happen with the 100 existing items. Unfortunately, when adding these fields to the editor for future scheduling, it is hiding all 100 items currently.

I was hoping that auto filling the neverRemove checkboxes would prevent the current 100 items from hiding and I would be good to go. In the future, I will schedule and manage the checkboxes as I create new items or edit old items as needed.

In conclusion, how can I add these 3 fields to my existing editor without effecting the existing 100 items? I am trying to avoid editing 100 items when I add these new fields. Maybe sometime on a site it will be 5,000 items.