Let me explain how ghost assignment works with this image.
Sakurai house is showing it will be haunted by two ghost. If none of these ghost are captured both will have 45% chance of appearing on the map totaling up to 90% and remaining ghost will have 10%. Let's say if you get Yule lady and capture her, next time when you play the same map it will have 90% chance for SCM-835 and 10% for remaining ghost. Once all listed ghosts are captured, if you go to Sakurai house again. There's a 75% chance for any of the two usually haunting ghost to appear.
SCM-835 only appears for two maps. One for Sakurai house and for apartment. In apartment it doesn't have special chance to appear so it will spawn less in that map.
Vicious Nurse was bugged until update 0.3.2.1 but now appears as it should in asylum map only.
Food doesn't give you buff? This is why I wanted to quit erotic games because people are only focused on sex stuff instead of actual game. Try eating one of each food item except okonomoyaki. You will see significant increase in speed. Riceball, sushi and ramen have a secret speed buff. Eating all food items negates speed debuff you get from eating an okonomoyaki. If you want to save money on food you can access Mrs. Yamada's phone to buy food items.
Furthermore, you get an equipment from doing a quest that give you 50% more speed with 25% less stamina. And you can speed up the game by pressing and holding M.