For me the best time was after choosing direct revenge or the event that started the alternate for Samantha. Both allow you to get the 60 lp required to trigger Emma AND don't have to worry about Samantha being girlfriend.I have a couple questions -
- When in the game should I start Emma's path? In my current playthrough I believe I have already screwed up cos I collared Bree, Sasha, Cassidy, Sam (after meeting Emma obv) etc. I have not explicitly asked others to be by gf. My interaction with Emma after the Watch Anime option did not go as per walkthrough (or I forgot about some interactions) and now whenever I see her, instead of her and Bree talking at the uni, the event where she askes to be friends triggers.
- After making Emma a gf/collar her, is it possible to continue with all the other girls?
As for getting her as girlfriend, yeah you're outta of the running for that. You needed to wait to collar all girls until after successfully raising Emma to 70 lp. You also should have held off on starting Cassidy period so as not to need to worry about her being a pet. I suggest next time activate Emma then the friday after doing so attend the office party since the 54 days between doing so and the investigation from Cassidy's path is plenty of time to finish her to that point and be safe.
The main point is the collaring. You could've worked around the rest. There is only one way you could possibly have fixed this and that was choose the 2 option on the date after watching Benji one since it bypasses the girlfriend choice apparently.