Going off only the singleplayer mode, the initial courses did feel similar and the strategies I used to clear them were too. With level design, since the hook is that you're using both players to golf at the same time, I think it would be cool to see the two characters working together instead of just golfing the same time in different spots on the course. How you implement that is difficult to say, maybe when one character is finished you can have them run ahead and interact with course hazards or use them to ricochet balls off of- sorry if this is off base for your goal with the game.
I do think the presentation is really charming, things like the balls knocking your teammate down are nice touches, I could see things like different girls having different idle animations they engage in when they've beaten the course and their partner is still golfing, adding some character to them.