This was fun experience with a dimwitted and perverted detective. You did do a good job making him not very sharp. As for the correct choice (I won't ruin the surprise) but, you could have used some flavor text from the motel owner to hint that something was amiss.
Obtaining notes about the case could prove helpful when questioning the motel owner. As for the menu you could use this plugin by mjshi that takes out all the battle info since it doesn't apply to the game. https://mjshi.weebly.com/mv-non-combat-menu.html