They have the instructions

Thiss iss ritual for ressurrecting her, if it musst be done again. Insstructionss are honesst, no trapss.

They have the flesh of his servant, who will willingly give

And Hermione, without waiting for any further instructions, said, the words spilling out of her in a rush, "I swear service to the House of Potter....

She has the means to find his foe, and forcibly take its blood

I figured out why we couldn't cast the Patronus Charm, Hermione, it doesn't have anything to do with us not being happy enough. But I can't tell you. I couldn't even tell the Headmaster. It needs to be even more secret than partial Transfiguration, for now, anyway. But if you ever need to fight Dementors, the secret is written here, cryptically, so that if someone doesn't know it's about Dementors and the Patronus Charm, they won't know what it means...

And Harry also knew that it was Thestral blood which painted the symbol of the Deathly Hallows on the inside of the Cloak, binding into the Cloak that portion of Death's power, enabling the Cloak to confront the Dementors on their own level and block them. It had felt like guessing, and yet a certain guess, the knowledge coming to him in the instant of solving the riddle.

With the bones of an ancestor (Potter, Slytherin heir, or Peverell), unknowingly bequeathed, they will have the final ingredient.

Prediction: Harry will die, and Hermione will resurrect him

(previous discussion)