Chococat could have a home added by this tent or simply make his tent the entrance to his home.
Kuromi could live above her potion hut OR the Haunted Mansion.
Keroppi could live above the nature preserve.
Hangyodon could live above the Comedy Shop.
Pekkle could live above the Dance Hall.
Pompomporin could live on his boat.
Wish Me Well could maybe live above the Greenhouse.
As for the CDs, maybe a jukebox added to the Dance Hall where we can sort through and choose anything to play. Im not sure if people want to actually display all of these since so many look the same, but if so maybe it could be similar to the preserve and donate the item and then it gets displayed in its assigned spot.
As for the fish, I like the idea of an upgraded preserve. Or better yet, what if each area had its own preserve where you donate critters, add fish to an aquarium, display the flowers for the region (the default one, not every one that can be planted, and the colors and pattern). Again, instead of giving an actual item for display, it automatically toggles on when we acquire it. (I'm just thinking maybe it would be easier for coding and gameplay having a toggle on/off for some of these things. But im not a coder so I could be totally wrong. Lol)
Then for flowers a place where we could display LOTS. I'm not sure how the best way to do it would be since there are so many combos. Maybe a room for each flower type that would have space for every color and the pattern/effect default to that flower. Then for pattern transfers or double colors maybe an area where we can display only a select number? I mean, in theory a place for every single possible combo would be amazing, but not sure that is truly feasible.