The walkthrough does have some problems, it has not always been updated so can be out a little. The issue you mention there is minor, so skip it and do some other things and check again later.
I ignored the issue until progression became hard-locked since you cannot discover the Hotel Cellar without finding the pages and discussing the settlers with the Library receptionist (or else Angela won't offer to sell the plan I think since you don't get the trivia chat about her previous studies on non-male PC), once I ran out of exploration/charm/dialog content in the game, I tried to spam search/re-examine in the history class to no avail.
I restarted from scratch and did not encounter the issue on a male/apprentice playthrough, but now i'm once again hard-locked at the Mother Superior's possession, which is impossible to cancel for some reason, even after taking the thrall and giving the relic to Sister Desiree. Neither clicking on the portrait in the upper-left corner nor using "cancel possession" on the right does anything. All I can do is move around the church with no way to leave the Mother Superior's body. Gina's possession did not cause any problem on the other hand.
I also appear to be unable to hypnotize Kate to recover gina's amulet after clearing the "press conference" event to get Gabby's necklace to use it on the PC's mom.
I will try to go back in time on my saves and pick an alternate path for Kate and finish the Legion path before starting Gabby's and see how it goes, but these random hard-locks are starting to become frustrating.
EDIT: Went for the path with Kate that does not give her the amulet, delayed mom and gabby's chain to do legion first, still getting hard-locked on the mother superior's possession after handing out the relic to Desiree. No clue what to do now.
