It would be really easy for Rumple to control Zelenas actions. “Why did you choose Regina over me?” “Ah because she is stronger willed than you are, Dearie. You could never have cast that curse. You couldn’t even recast it today through blood magic, because it requires Regina’s blood, and you could never get Regina’s blood.” “Ha! You think I can’t recast that curse? Watch me!”
And being her mother’s daughter, if someone tells her she can’t do a thing, she is SO gonna do the thing.
“You should never have brought me back.” Ah, but isn’t he exactly where he wants to be?
Hmmm, that’s sort of a loaded question IMO. On the one hand, we’ve seen him move worlds to get back to his son before, so sure, it’d be fitting for him to strive to get back to Neal (and Belle) again. But on the other hand, he seemed perfectly willing to accept his fate in 311, because he felt it was the price he had to pay. He’s got enough experience under his belt now to know that messing with the fates and trying to avoid paying your price will mess you up, so would he accept that he should stay away, so as not to bring any more doom and gloom into the lives of his loved ones?
That being said, I’m sure that when Zelena brought him to SB, he wasn’t exactly bummed about the prospect of seeing his loved ones again, and if it wasn’t his doing in any way that he’s back there in their general vicinity, then his hands are clean and he won’t have to risk paying a price for the magic that makes that reunion possible.