#i’m still confused about their plot line js js
Not a plot line. A plot hole.
These two episodes explain several things. All the things it explains are in bold and my reasoning is underneath.
It explains why Cora signed the contract.
Cora is, basically, bitch-slapping Rumple as she knows the truth. Zelena is gone and Rumple can’t, as far as she knows, get her first born - he may know of Zelena, but he cannot get to Oz; if he could, there’d be no need to send Jefferson to get the Slippers! - so she wins on all fronts: she gets power and prestige and successfully brokers with the Dark One with no ill consequences.
For Rumple, it was a case of getting what he wanted - Bae - and putting everyone into a position for him to use.
He choose Regina as Zelena, to him, was petty, unable to put her envy aside and would not do what he wanted - she would solely target Regina, as she does in Storybrooke. She goes off on a whim, turns green, turns Walsh into a monkey and tried to kill Regina… everything Rumple wanted to avoid as it was his plan to get Baelfire, not Regina.
Regina, on the other hand, was always plotting on one cause: Snow White’s suffering. The Dark Curse would give her that and give Rumple what he wanted. Thus, for Rumple, the choice was simple: drop cazy psycho bitch Zelena and apprentice Regina - he’d waited 300 years already, so another few years while Regina learns is nothing as long as his plan worked.
As for the stuff with Eva tripping Cora.
Eva knows who she is and it has a double meaning: it was a warning to keep her away from Leopold again as he and Eva are presumably not married - there’s eight years between Regina and Snow and the former is only just born at the end of The Miller’s Daughter - and is also Eva gloating and saying “I won - go home, bitch!”
That’s also why Cora is so angry at apologising to Eva - Eva’s already fucked up her prospects once and could have done so again by embarrassing Cora there.
It explains why Cora poisoned Eva.
Cora would have had Leopold but Eva fucked it up. With Eva dead and Snow having been saved from the bolting horse that Cora caused, there would be nothing in the way of Regina becoming Queen.
Then, Snow revealed Daniel’s part in the problem; no matter - death to the Stable Boy who could be replaced and was collateral damage.
With Daniel dead there was nothing - Nadda, zilch, el zippo! - in the way of Regina’s rise to power and Cora’s rise with her.
And, indirectly, it all worked; Regina became Queen and had everything Cora wanted… and thanks to Regina, Cora became Queen of Wonderland and true royalty herself.
See? It all makes sense.