I think that sounds fine although how big is the utility room as rabbits are active at night. Regarding temperatures you just can't let them be warm then go outside in the cold. But you seem to know that. If they are inside in the warm they will moult but won't have such a thick coat. I don't think they'll get too warm. Doughnut is an indoor bunny and she's used to the heating being on. When the sun is out she goes to sit in it. Obviously you have to make sure they don't over heat but consistent temperature is best.
She loves tunnels so that could be something for the utility room. I've just bunny proofed downstairs so she has free reign and I put her out in a run in the garden in the summer. I always supervise that though as cats can r scare her even though she has hiding places.
Generally rabbits don't like being picked up so they aren't cuddly pets but you can normally gain their trust and they're happy to have nose rubs and give kisses on ground level.
Are they vaccinated and neutered. Rabbits aren't cheap pets so getting insurance is advised.
Looking forward to seeing the photos of them