I could see Cora and Eva having been estranged sisters to the point that Eva never told Leopold she’d had a sister. Perhaps whatever goes down between Cora, Rumple and Henry is such a hot mess that it brings shame to her family and they disown her, so she cooks up the plan to kill off her sister and have Regina marry her sister’s husband as a means of revenge. There’s gotta be some reason that Cora chose Leopold and Snow in particular, I don’t believe it was mere chance, because Cora is nothing if not calculated. If we go with the theory that Cora is the one who killed Eva, then there’s gotta be a motive, and being sisters who’d had a major falling out could potentially provide that motive.
Was trying to figure out how their ages would all fit together to see if it’d work that Eva and Leopold could have met after Cora had become estranged, but it’s tricky when we don’t know exactly when stuff happened and how old they all were at certain points.
How old do we reckon Cora was around the time she and Regina met Snow? Late 40s – 50ish?
Snow was 12ish around that time. We don’t know how old she was when she lost her mother, but if they’re getting Bailee back for this ep, they can’t make her much younger, so let’s say she lost her mum when she was 10ish?
The casting call for Katerina(Eva) was for a 40 year old, (Rena Sofer is 45).
So a couple of years before the events of Stable Boy, Snow was 10ish, Eva was 40, and Cora was potentially 40ish too. So if Eva and Cora were sisters, there probably wasn’t much of an age difference.
However, there’s a significant age difference between Snow and Regina, probably close to the 10 year mark, if Snow was about 12 and Regina was about 20 when they met.
So if events surrounding Cora marrying Henry and having Regina resulted in Cora being kicked out of the family, that still allows 8ish years for Eva to meet Leopold and have Snow, which makes it believable IMO that Leopold never had to know that Eva ever had a sister if she was never spoken about after she was excommunicated.
Granted, it’s all just speculation at this point, but if they did plan to make Regina’s mother and Snow’s mother sisters, I doubt they’d have given any hints to suggest it before dropping the bombshell, coz it’d be a pretty huge bombshell that they’d wanna shock people with.