Thanks for the translation! I don't know how this manga ends (although I do know that it's over) but from what it seems so far, it looks like Midori would be a better mother for Misha than Tsubame after the latest developments in the last few chapters.
I don't know if the stepdad's ever going to get remarried because this is a Yuri Manga, but if he did, Midori wouldn't be the worst choice.