I won't do it technically, but I'll think about the characters and the plot.here is my suggestion for the story:
PUT IT ON HOLD AND FORGET ABOUT IT - until UFO is finished
You have not the ressources to do 2 games at once - you will mess up both instead of doing ONE game right.
Even big developers like MrDots who tried to do 2 games at once nearly messed up and quote "NEVER EVER i will do 2 games at once".
Aside that, i like mother 1 and the general setup could be fun (but please no ntr in front row).
Even i strongly advice NOT to do 2 games at once, i am looking forward to see this game one day (but please finish UFO first)
Create character prototypes.