They ar not approved. When you create a custom NPC/item you get it in your inventory but it does not spawn until it gets approved, whereupon it will spawn at your location. If its declined it will be deleted from your inventory.
There has been a SIM news about custom art and NPC requests.
“Custom Art Bug, please hold...
(Posted by Jevon Lambright on Year 13 Day 182 20:07)
We are currently experiencing difficulties with both custom item and custom NPC image acceptance/declining. In order to prevent overloading our custom system with them, we ask that any and all future Custom Item & Custom NPC requests be withheld until the system has been restored and fully integrated into the new custom system
We thank you, the Art Team”
Since there has not yet been an official communication that they have restored the system, I suspect you must wait for that.