I've started playing around with some early-game routing

As for a definition, I propose:

• saving Jun
• collecting one of each weapon (equivalent of Fully Equipped trophy)
• all Small Keys + their chests (equivalent of The Keys To Success trophy)
• the lore you can actually pick up (Jedidah's Letter, Written Notes, Generic Reports, floor plan of the hospital in Chapter 8, etc.)

I doubt whether all lockpicking with Stan or hacking with Mei should be included, seeing as most rooms behind those doors don't contain special/unique items.