Get all Blood Memories & notes, then head to Library 3, & go all the way up. You can now examine the windows.

You need to examine the windows in a particular order, which is based on PlayStation Trophies. https://psnprofiles.com/trophies/6032-a-rose-in-the-twilight/ Start from the top, going down. The title of each Trophy corresponds with a star, rose, or bird.

If you still can't figure it out, here's the answer.
1) Rose
2) Star
3) Rose
4) Rose
5) Star
6) Rose
7) Star
8) Bird
9) Rose
10) Star
11) Bird
12) Rose
13) Rose
14) Bird
15) Rose
16) Bird
17) Star
18) Rose
19) Star
20) Rose
21) Star
22) Star
23) Rose
24) Star
25) Rose
26) Rose
27) Bird
28) Bird
29) Rose

To get cat ears, examine the Statue in you Collection, and choose "Yes." If you want the crown again, do the same, but choose "No."
Thanks to Liar Princess and their friend, Oni (a.k.a. Kindred), for letting me know this even existed.