I think I have figured out the missing last 112th unlocked item. I went back to all the previous stages and select all items to play in different levels. I am sure I have unlocked very single item.

But one item I found out that has a glitch. In stage 4, there is one item Shovel to Watering Can to Boots (under the counter). I realized that ever since I have selected Boots, no one ever ordered this item. When I click on it, Emily will just shake her head and refused to put in the tray.

I think this glitch is causing the game to not recognize this Boot item as unlocked/usable. My game version is the old one, Level 57 requires 1,500 tips. So maybe the newer version has this glitch rectified as well.

I hope this helps anyone. I too spent many hours trying to figure out why I still cannot find the missing 112th item and complete level 57.