Magical Melody brings back the bachelorettes from the SNES original and gives them romantic rivals for the first time. When you consider that the bachelorettes from Harvest Moon 64 are supposed to be descended from the HM girls, you can notice some family resemblances:
In Magical Melody, Ann pairs up with Blue, who looks an awful lot like Gray from HM64. Since Gray was HM64 Ann's brother, that means Blue is his grandfather!
Nina pairs up with Basil, who looks just like Popuri's father from HM64 (also named Basil). Since Popuri looks so much like Nina, she's probably her granddaughter, which would make MM Basil and 64 Basil father and son.
Magical Melody has many characters from Save The Homeland, where the plot of the game was to find a way to save the town from being bulldozed and turned into a theme park. It's not too hard to think of MM as a sequel that's based on what happens if you fail in the previous game. Then again it could easily be an Alternate Universe.
In Magical Melody, when a typhoon comes in the middle of summer (or snowstorm in winter), you are stuck in the house with your pets until the storm escalates once you return to bed the next day. When you check your records, Jamie somehow managed to deliver crops that previous day despite time does not pass when you're indoors, and you cannot go out, rendering you to have to skip the day. Jamie must be one hell of a Determinator just to ship his/her crops.
