Even if your fetish here is solely connected to the object, the association the object has with a child is going to get you in trouble one day if someone vanilla catches you. If you really do have a fascination with poopy diapers that smell like baby wipes and baby powder, I'd advise buying your own diapers, pooping them yourself, filling them up with wipes and powder, and smelling your own messes, and do it exclusively in the privacy of your own home. That way, you remove the association the object ever had to a child and it remains your own private business. Now, you do still need to be very careful because this is a good way to get yourself sick, but it sounds like you're already taking precautions when it comes to that.
Stop dumpster diving though, and while you're at it, burn the photos and get rid of the folder you have of pictures of the diapers you've already collected. That's super-creepy and you will get in trouble if you keep doing these things.