There are so many references to the player entity itself throughout the savegame that I'd consider this hard to do. You'd have to remove every reference to the deleted characters handle to completely delete them (eg. remove them from EntityWorld, OsirisVariableHelper, InventoryManager, CombatComponents, CharacterFactory, ...).
In addition you'd have to patch story databases to make sure that the character is gone, otherwise you'll get weird game bugs (there is currently no tool to do this).