Reading the Novel Trilogy

We know that Henry can add and alter memories, so surely he can remove them too. Afterall Charlie remembers Spring Bonnie taking and fleeing with Sammy when we know that Charlotte was the one that was taken.

And it's very likely that Mrs Emily and Aunt Jen would have talked about Charlie's animatronic nature in front of her, memories/moments that Henry would need to erase.

Honestly Henry probably altered/erased any mention of Sammy, Charlotte's fate and Charlie's nature.

Also the main passages about Mrs Emily that come to mind are these:

This one is very vague. It's exhausting to think about, as if Charlie is forced not to think too much about herself and Mrs Emily. It's likely Henry input this false mutual tension to discourage Charlie from seeking Mrs Emily out.

This one is also vague. But it makes sense to me that Charlie wouldn't remember Mrs Emily saying goodbye, because she probably didn't, not to Charlie, who she would see as the robot that Henry was trying to replace their dead daughter with. Why would she say goodbye. She probably either just left or maybe had one final plead to Henry, possibly even mentioning Charlie's robotic nature, before leaving for good. Sammy might have been with her or with other family.

In the case Sammy was with her. he may have seen and even remember Charlie, but I doubt Charlie would remember those moments.

Any of her memories with Mrs Emily at this time are likely manufactured by Henry, as I doubt Mrs Emily would even want to look at Charlie at all, nevertheless interact with her, which was probably just Mrs Emily talking to Henry with Charlie in the background.

So sadly any mention of Mrs Emily from Charlie's POV post-kidnapping is likely heavily doctored by Henry and therefore unreliable. So no real Charlie and Mrs Emily dynamic.

"but could not bring himself to get rid of the snake."