I think the image is saying that maki x hanayo is the parents of hanamaru because of the similar looks. Which would explain hanamaru eating disorder and being quiet. RIP to all the hanayo x rin and maki x nico fans.
Most official artwork that pertains to the Fate/Extra games are depicting this pairing anyway. Heck, even the official poster for the game released during the anniversary two years ago used this couple.
This is my favorite pairing in the Fate franchise as well.