> They're all going to receive a blanket pardon.

To the extent that their actions are unlawful, they are often crimes under state law in the states they occur, as well as federal law. The President of the United States has no power to pardon state law offenses (and while there may be political considerations that discourage pursuing charges while it might provoke conflict with the Trump Administration, but in many cases the statutes of limitations for violent crimes under state law are not short.