Cora’s not interested in Rumple so I don’t think she’d be bothered with Belle. In fact she might want to keep Belle around. If love is weakness, then Belle makes Rumple weak.
Hook is the one to worry about. Although I think he may try and steal Belle away from Rumple rather than hurt her in order to make Rumple suffer before he tries to kill him.
I agree. I think Cora and Hook both have separate targets. Hook wants revenge against Rumpel for killing Milha, and Cora wants revenge against Regina for pushing her through the looking glass.