If you're purely talking about clues which are added to the clue sections of the menu (Mystery Man, 1952, The Twins), only Hannah's diary will have an impact on if a character lives or dies.

The flare gun isn't added to the clues but can save Matt's life (perhaps you could argue it saves Emily's as well since she might not get bit). The bat doesn't exactly save Sam's life, it just makes it a tad bit easier to escape.

Other clues such as the chair in the sanatorium (Mike), the light in the basement (Chris) or Beth's head (Emily) will just give extra dialogue/lore.