I think your fear about opening up to your therapist is completely understandable, and just about anyone who'd experienced that would feel exactly the same way.
Also, you are blessed to have a T now who is so kind and safe. Sounds like at least one of your little parts trusts her and wants to get closer. If and when you do decide to bring those items, I'm sure your little one will feel very supported.
Does your current T know about the other one?