As far as Belle and Sidney go, I’d love to say they have brotp potential (BeautyMirror?), but seeing Giancarlo say he “still is very much in love with the Queen” makes me think that if he gets out of the dungeon, and discovers Regina is gone, he’s not gonna wanna work with Belle if she’s attempting to run SB in Regina’s place. If he could get past that blind love he has for her, he could see that he and Belle have some stuff in common they could bond over. But if he’s still devoted to Regina, then Belle is just the Dark One’s girlfriend who Regina used to hold prisoner, and how dare she be running around SB free as a bird, trying to take Regina’s place, while she’s off God knows where in some kind of danger.