Its an odd coincidence that the woman who happens to open the urn is the woman whose parents were killed by the sister of the Big Bad so many years before. In another country, no less.
Fridge Brilliance: Mater Lachrymarum is actually the weakest of the Three Mothers, as she does not have her sister's powers to draw on. This is why her home, the Palazzo Varelli, has fallen into disrepair, and why she has to rely on the tunic to give her power.
Fridge Horror: In Inferno, there's a BLAM moment where a caretaker and another woman are gleefully examining a large piece of meat. When Mark approaches her to ask a question, the caretaker tries to cover the meat, as if she had been caught in a compromising position. No explanation is given (to be fair, there's a lot in that film that's never explained), however, Mother of Tears, its sequel, establishes that evil witches in the Three Mother's 'verse are cannibals.