That can work, but I found you can also safely work with Sasha and Bree provided you only have sex with Bree once for unlocking the second half of her route, and for Sasha no sex but have successful first date is ok as long as say no to coffee and just don't talk to her at meal time if you accidentally raise her kp to 75 plus until Emma is done.So basically start with Sam's route exclusively in the beginning, then get Emma and THEN start with other girls?
There are 2 girls you can fully finish route wise but don't collar and be ok. The wiki says 3 but the third is impossible to finish since it requires Cassidy and you know she's a none starter. 0ne is Palla, since she is actually like Audrey in getting off to the MC fucking other girls when she knows. The other surprising is Lexi, and she can't be collared anyways until after Samantha and Sasha so finishing her main route is fine. I think like Palla due to her openness in regards to sex and overall dumb nature Emma doesn't consider her a problem lol.