I wish I saw Cassidy to relate to the banter above. I've not seen the character nor played with her in gameplay so I have no opinion. Although I do restate the opinion that the game has strongly redeemed itself on the gameplay front, for the reason that doomsaying against the game got pretty common with the project's lack of direction. The game has improved so much that I'm actually shocked the project didn't become vaporware. It would shape up to be a great game provided "progression" is implemented well.
Here is what I feel about future progression. It's an arcade game not an open world game, so I would recommend more levels overall. Players don't care about unlockable clutter. Players like RNG despite some loud voices against RNG, since replaying a level again isn't fun without difference. One can argue that having certain mechanics of levels themselves be influenced by RNG is a smart move.
Unlockable side-games are a smart move. I think unlockable aesthetics can be a smart move if they were more notorious, for example X unlockable minigame High Score unlocks Y item or some challenging objective like keeping the chubby dog girl in your doorway (a risk) for X amount of time for an unlock. Maybe a difficult challenge, like refusing to look at the hallway where the evil version of Ari spawns and creeps for at least X amount of time. Purposely aggro'ing Nile by refusing to keep camera on her all run, never looking away from Sammy when she stares at you, breaking the microwave yet still surviving, never closing the gas leak, etc.
However a balanced game does not benefit from powerups on top of a flat foundation, so it is a bad idea to make "plushies" or such give the player an easier time since the "good" gameplay gets "boring". It can be valid if it was a "trade" not a "buff", for example an alternative plush giving reduced sanity benefit in exchange for a good trait or more sanity for a bad trait. For example, a plush of Nile the Egypt-themed jackal will give a large sanity boost in exchange of Nile resetting her affection bar and immediately pressing herself against your window, which is a cost to battery power for locking her out and a time risk for being inefficient staring at her earlier / having to repeat that job next time she moves back to the map. Or something simpler, like a plush that gives less sanity per use but makes Sammy the Tiger "repel away" when used. Do note that any system of stat exchanges like this takes a crap ton of balance work, which is why I say give them good unlock criteria for style first and then incentivize later (optionally) using this approach if you think unlocks should have more attraction to players.