my advice is, START SMALL. too many developers try to make the second coming of the witcher 3, and stumble because they cant even make the characters interesting.
focus on 1 character at a time. its ok to hint or present a new one to entice the players, but focus on 1, get her base done, move to another, when possible go back and add stuff to the first so she feels fresh. rinse repeat.
dont try to make too many cumbersome "1 time" events, no need to develop a Chess master AI for a single match.
if you are gonna do mini games, offer choice.
animation is good, but is not vital, if you have to choose, work on a better dialogue(that isnt too wordy), and later, when you have the time, implement the animations.
finally, make each segment its own thing, im not talking about each girl one game, but when making the code, dont spaghetti, make a template that can be reused for each new girl. it will work better on the long run.