Okay so, while I had a lot of fun paralleling Mafuyu and Haruka in the fic, they also just have So Much in common.
Identity - Haruka doesn't know who she is if not an idol; the double date with Anhane showed a side of Haruka she left behind in the past. The last thing about Haruka unrelated to her seven or so years in idol hell is her love of penguins. Mafuyu obviously has lost sight of who she truly is as well; she wants to rediscover her true self. Minori wants to bring out Haruka's best self [Haruka the idol] while Kanade wants to bring out Mafuyu's true self.
Food - Haruka of course has a severe eating disorder. She's lost the ability to break her diet and so frequently is shown wishing she could eat but she can't. Mafuyu doesn't care for food at all; she can't even taste it. It's meaningless to her.
Hope - So, I think this flies under the radar because Haruka herself is trying to hide it from Minori, that Minori didn't magically give Haruka back her sense of hope during the main story. Every single time MMJ gets faced with some conflict or challenge, Haruka consistently sees right through to the messiest parts of it and her response is generally to caution the others to be ready for the worst-case scenario. But also, she's often blind to the solutions Minori comes up with. Part of that is because of Minori's unique perspective as a dedicated fan, but it's also because Haruka just doesn't have that kind of optimism. While I want to say Mafuyu also lacks hope, that isn't true. Mafuyu is willing to take any bet because she has nothing left to lose and everything to win. Kanade frequently challenges her to take steps forward and we get to see exactly how agonizingly difficult that is for Mafuyu, but if it's hell where she's at and hell to move forward she'll move forward.
Adoration - This one covers two things. Mafuyu and Haruka are each very popular. Mafuyu is constantly helping her classmates with schoolwork and is praising and being praised by them and Haruka is Haruka. But, Mafuyu herself doesn't care for that attention, except when it's from Shizuku, and when it's with her, Mafuyu fights heaven and earth not to let Shizuku know she's depressed. She wants to be the beacon of hope Shizuku sees her as. Likewise Haruka consistently views fan interactions as a hazard unless those fans are children in which case she goes out of her way to be Haruka the idol for them.
(Adoration) - Secondly, Minori is obsessed with Haruka and Kanade is obsessed with Mafuyu. Minori tempers her obsession with challenging herself to view Haruka for who she is as a person rather than who she is as an idol, and Kanade had a whole event about destroying herself trying to understand Mafuyu's pain from Mafuyu's point of view. Kanade's warm music and Minori's fangirling aren't enough and they each know it. Likewise, Mafuyu and Haruka treasure Kanade and Minori in roughly the same ways.
Masking - Mafuyu and Haruka have each spent, honestly, about the same amount of their life forced to mask and act out a persona in every aspect of their life. Mafuyu is her mom's 'good girl' and Haruka is Haruka the idol. Both of them, were nothing else. Both of them lost their old persona. However, while Mafuyu's trying to no longer need the mask, Haruka still puts on an act for the camera; she chose to forgo her own My Color moment.
Safe-space - Running is kind of sacred to Haruka. Sure it's part of her fitness routine which she enjoys maintaining (as opposed to her diet which she also maintains), but the opening montage to the idols dressed as shrine maidens event alone shows that running is when Haruka feels most at peace. Music, of course, is this for Mafuyu. Nothing makes Mafuyu feel the way music makes her feel. She very materially needs her work she does with N25.
Future - The unspoken part of MORE MORE JUMP!'s story is the context which does not need explaining to a Japanese audience; idols sort of fall off the map by age 25. We actually got to see it happen with Haruka's Idol who she saw a vision of in World Link 1. It actually isn't important whether that was the actual truth of what ever happened to Haruka's Idol or if it was Haruka fantasizing of the best-possible scenario for her life. Shizuku, Airi, and Minori all have their best days as idols ahead of them however, while Haruka has hers behind her; even among idols [who have no futures], Haruka has no future. Mafuyu, of course, would die if she continued on to medical school; her story centers around her having no future.