Following up: I'm following the guide and on day 14 when I go to the market, I actually meet with the queen and don't get any option to buy a potion. While meeting the queen does bump me up to 25 knowledge, without the potion and I guess stat points didn't count enough, it seems like I'm not able to get information out of the bodyguard.
*Edit: yea I'm willing to say that the guide does not work for 2.0, while I can get all individual endings, it really breaks around day 20 or so as there aren't any options to go to certain areas at times. I was able to get one duo ending, but not either harem ending, and as noted I wasn't able to buy the potion. I actually wonder if the game's difficulty settings were in place when the walkthrough came out. Also the gallery mod kinda works, you have to ignore an error, but the mod doesn't seem to add the new characters so it won't work to see the DLC stuff early. Hoping someone puts out a proper guide. I will say that since the potion event didn't trigger and once I got bumped down to easy I was able to get the documents in the office, money didn't do anything for me.