and yes there are 2 ways to play it through. The 1st normal ending without being deflowered. That gives 1. item where you can switch everything so freely. 2. Varaiante is the more difficult because there are only places where you can lose stars.
on the umlf page there should be a solution.
Part 1 At the auction in the desert town.
A star loses if the action takes part and there only 0 pays or loses .
Part 2
The item you don't get from the auction will still be available in the mansion to the north by completing the maid quest and opening the locked door on the second floor.
part 3
Received from the Yuki-onna in the ice dungeon in the south part of the ice continent. (Requires freeing all the frozen people in the northwest village on the same continent with the item created at the academy)
Cursed trasuer
1: At the top of the incubus tower, west and slightly north of the initial castle. (Requires a magic key to unlock the door)
2: At the auction in the desert town. (The desert continent requires a ship to get to. Either 10k per passage or 100k to buy the ship in the NE town on the initial continent)
3: In the basement of the mansion north of the desert town. (Requires talking to the owner after the auction and equipping the maid uniform; might also require talking to NPCs in the snow castle dungeon and slums - haven't tried getting it without having the info about it first)
It doesn't matter the order, you always lose 1 star.
Edit
I puzzled together what was in the ulmf page of information