these two are going to be the best parents. Crona because he will learn from all Medusa's mistakes and do everything to avoid them all while trying to be the father for their baby he probably wished he had since there is no mention of his dad in anime or manga even once, not even by Medusa herself. He would have been adopted by Marie and Stein, with Marie being the one who was a real mother to him and stein being basically a team dad for everyone and adoptive dad for Crona (possibly biological father?). Maka because she would have learned from her parents mistakes as well, her dad for having more loyalty for Crona than he did for her mom, and her mom for knowing not to date her partner soul eater and never to leave her kid for anything