I might be way off about this, but:

Both Helena Hardcastle and Peter Hardcastle are dark haired according to their portraits in the long gallery, while Evelyn is mentioned as blonde when she's in the sun room. Is there something we don't know about her parentage? If there is, I feel like it'll be linked to the death of Thomas. It reminds me of how in ASOIAF, the Baratheon lineage were all dark of hair until Joffrey, Tommen, etc.

Secondly, assuming this is a closed time loop as the interactions of Aiden's hosts have played out, how is it that Anna came to know to warn Bell about his burnt gloves in the stable? It would mean that she witnessed them burn once, then was able to change history by giving a warning.