Thanks for posting with an excellent question. You've discovered one of the messier situations and this can get a little cumbersome, but one quest line had to take priority over the others as Mindy couldn't be in two places at once... I just imagined it as her putting everything else on hold for Misty, but more to the point, you should be able to proceed with Misty's quest line and then if all else remains unchanged, Jack's should be possible to resume after Misty's is completed.
That said, it's possible there could be bugs of this conflicting-quest nature that eluded me, so if you try that and it doesn't work out for you as I've described, please reach out again and let me know so I can look into it more thoroughly.
My apologies for the strangeness of the setup, but thank you for trying the game!