This is almost correct, you just need to have completed rosaria, Sucrose, Lisa and mona Co op pranks first, as well as buying all items and junk, and completing the tax commission.If you're following along the walkthrough like myself, yeah you encounter this issue when the directions are provided.
The solution is you have to do everything else first. All the events that trigger clothing, you have to buy those clothes. Mona's cauldron? Do that. The photo book? Yup, that too.
Easiest way to check is by buying Mona's cauldron and checking if all the events are done except one remaining scene of Hu Tao, then make sure you buy everything from Hu Tao. Only then does the co-op prank open up. Also, make sure you have 1000 coin left over too because Hu Tao extorts you to start that prank. It's scummy, but she gets hers in the end!
I'll add a hint that makes it more obvious next update