5. Rejects And Candidates List
One of the later notes found isn't actually from the servant of the house in 1958 - it is a list of names under the banners 'Candidate' and 'Reject'. Considering the vampiric implications as well as how we know a ritual is happening this could be one of two things: the candidates are going to be used for the ritual as a sacrifice or a vessel for something horrific and evil, or they are going to be turned into new 'vampires'.
One thing is for certain; the rejects get made into wine tactfully named Sanguis Virginis or 'Maiden's Blood'.
The three names highlighted as the candidates could also be the three daughters - at a stretch. It definitely seems like a happy coincidence that there are three daughters and three names highlighted specifically as 'candidates' for what could be an infection or being turned into a 'vampire.'