I remember Leap of Faith, in the first 4 chapters you can fool around with every chick of the game, with someone just teasing, others a kiss and others even sex (and, by definition, the first 4 chapters are HAREM style). Then the game itself lead you to a choice, from that point the story develops around the girl you choose and only her, while keep interacting with all the other girls only as friends (in fact, even if you want to be a cheater, you can't because the game itself forbid you from doing that). According to the girl you choose, if you play the cards well, you can end up with a 2some or 3some where everyone knows about the other and they are fine with it.
Back to WTHI, as long as you are able to be with every girl, whether they are aware of each other or not, is HAREM by definition.
You can argue about the fact that in this case is not an harem because you basically are cheating everyone with everyone, but is just a semantic issue.
If you devs don't want us to consider this game a harem, then the famous BIG choice must happen before anything serious happen between the MC and any of the girls.
Of course, after the decision you can always make ground for 3some, 4some or mini harems (like Katie/Lily/Debbie, or Jenna/whoever or Monica/Zarah) according to what the story itself requires.
I hope I made myself clear, English is not my mother tongue, so apologize for any grammatical horror.