Nothing wrong with incest so you as you don't muddy the gene pool. Of course if neither of them know their full-blood siblings then... yeah. Just do as the busty wolf said and breed with her.
The queen is kinda stupid not to use her position to bring all year round scarf wearing into fashion... not like any magic was done to melt clothing that touches the collar.
Bruh the story really is going in the direction of the eminence in shadow. Also can someoene tell me will haruto reveal his situation that he's the son of the king & queen to others later?