How is Hector impacting and challenging everyone around him through Memory?
What about the Past is a personal struggle for Miguel?
I kinda posted my opinion on the subject at the beginning of the topic, but here's a bit more : Hector wants to be remembered by his family and being forgotten would be the end for him. Not only is it his greatest concern throughout the story, but it creates all kind of havoc around him : bitter memories from his ex-wife is what drove the family away from music, directly impacting Miguel and his passion as a result ; him manifesting his presence once again creates tensions with his family members ; De La Cruz wants to prevent him from being remembered as the composer of the songs (by killing him and then trapping him in the land of the dead) and threatens to get at him and Miguel if that were to happen... "Contrasts with Miguel who clearly stated at the beginning that he didn't care about being remembered and would rather realize his dream than being part of a family like his. Hector's the most fit to influence him." (but this one applies in the context of a Changed MC, as it feels more like Miguel adopted Hector's view of how important it was to be remembered and how "Family comes first" without him giving up music, it's more like he shifted his priorities)
As for Miguel, his family's history with music hinders his growth as a musician. He is forced to become a shoemaker and to hide his passion ; at the same time, his fascination for historical icon of music Ernesto de la Cruz, as well as his great-great-grand father that everyone seems to erase from family's history, prove to be a touchy topics for everyone in his family, making it a constant struggle for him. I believe issues of Interdiction, Prediction, Fate and Destiny resonate strongly with Miguel, just like Truth, Falsehood, Evidence and Suspicion work for Hector.