If I delete a field from one layout, will it be deleted from another layout where it is used as well?

If I delete a field from one layout, will it be deleted from another layout where it is used as well?

No. If you delete a field from one layout, it will be pushed to the Unused Fields section for that layout. It will not be deleted from another layout. You can bring a removed field back to the layout from the Unused Fields section.