Let’s work with facts and couples here:
- Stefan is human, Caroline is a vampire
- Elena is human, Damon is a vampire
- Stefan and Elena can’t be turned into vampires again
- Damon and Caroline can’t take the cure from Stefan without him aging fast and dying
- Bonnie probably has her powers back and lost Enzo, so she won’t want to become a vampire (but the necklace with Enzo’s blood still bugs me)
- Matt, well, he is still same old Matt.