The manufactor has been delaying the adds without any notice. I've been in contact with them since the start, checking regularily with them (usually once per week).
Robin and Salome were supposed to be out on December, but some improvement were needed on the final product and they decided to delay their release (I saw pictures of Salome's sculpt, and he looks nice, I'll share them once he is painted). Brook is next on the production line, alongside Kizaru. Unfortunately, the sooner they might be out is March, since February is Chinese new year and the factory will be closed all month.
There's nothing else 1Up or I can do about it, just to ask for your patience. And thank you for the support!