Since trying to figure out what the memories are isn't working, maybe a different approach might work better for you. Maybe folks inside need to feel safe before they can begin to look at the memories. You don't have to know the exact memory to be able to respond to fear.

I've found that my parts often need me (or someone else inside) to comfort them and help them feel safe, just like any external child would. I hold them (I have a doll that represents my parts externally), rock them, talk to them gently...again, just like I would with any outside kid who was scared. I've also found it really helpful to work with them to create their own safe places where they know nothing bad can get them.

I don't know if that helps you or not...just throwing some alternate ideas out.