I'm not a developer. But after having played through Act 1, i can assure you those aren't bugs.
Firstly, the hints. after the linear part, you are given a bunch of objectives to be completed in any order. The game explains that hints are disabled due to Sonya not knowing what the main character did during these free roam non-linear parts. If you're getting stuck and don't want to resort to a walkthrough, i suggest you regularly check the journal, as it provides minor hints as to what it needed to be done.
The Prefect papers are located in Dumbledore's desk. after the first time you try to read them, you'll need to either progress more with the girl's who wrote the respective paper or upgrade your stats.
If you need help progressing through the story and getting achievements, i recommend this google document.
https://docs.google.com/document/d/1nc733oxh_dlxQwF9tPBlyzlltR5cEEAhA07D0soKxlY/...
It's not completely up to date, as Daphne's minigame is missing alongside a couple achievements. But it should help you for the most part.