If you try to follow the walkthroughs, you are just reproducing someone else's playthrough of the game. That's the biggest reason why I wrote the guide - because I wanted something that actually helped figure out how to get unstuck, without forcing me to do exactly what someone else did when they played the game, and to make it easier to figure out what actions I had to take in order to complete quests, without spending a lot of time studying the walkthrough to figure out what action on what day was necessary to unlock a choice or reveal a clue.
But no, you don't have to send Evelyn off to seduce Callie. Some other stuff that the walkthroughs include but which is optional: you don't have to romance or enter a relationship with anybody - it's possible to win the game without any girlfriends at all. You don't have to spend any time at all molesting women in their sleep if that's not your kink. Once you have entered a relationship with someone, you don't have to spend any time slots repeating sex scenes with them.