If you want the items to appear in a certain order, you could manage it with variables that get added to each time the player interacts with an item, and have the variable count trigger the change to the new room instead of putting it on a tile. That's how I did in my game/poem The Opposite of Brontide. I had multiple items in each room so that cut down on the amount of identical rooms needed, but it should work the way you are thinking, and because it's tied to item interaction, it's less likely someone will accidentally step on the warp tile without interacting with the item.

But if others have more elegant solutions, please chime in!

You can stack items by editing their coordinates in game data (which you can find in tools > game > data) by changing x and y values to be an exact match, example:

ITM 1 1,6

ITM 0 1,6

The item with the lower ID takes rendering priority and is the only one that appears visually, all other items share its layout. However, each item still keeps its own dialog definition if you’ve assigned unique dialog.