I know there is already a way for you to put your retainers outside of your house. There could be something similar where you could customize the appearance of a manikin but it would turn into a statue, but unsure how hard it would be to implement. I know for the manikin system you can tie your retainer to it and summon them through the manikin, so making it so the player is the retainer but someone getting them instead of being the retainer just be a statue of the player if that makes sense. There is already sort of a way to get none player characters though they are shop keeps or retainers but they are custom already so making the same system to make a statue customizable shouldn't be too hard but you would have to just tie into the system that is already there.