Let’s all back up and talk about visual thinkers.
People who are strongly visual thinkers tend to have thoughts and imaginings that bubble up in a visual form, without consciously willing them. This is no different from intellectual thinkers who tend to have ideas pop up in an intellectual form, or audial thinkers who suddenly “hear” music and compose tunes that way. I know a fair amount of people who are like this.
Any kind of person can become a fiction writer, but it is very common for visual thinkers to think up stories and characters by “seeing” them just pop into their minds. One good example was the fantasy writer Diana Wynne Jones, who said that it was easy to get a story idea – you just visualize a street, and then you visualize walking down the street, and you just write down what happens! (Obviously there’s a lot more to it, after that, but that was how she started her work.) I’ve heard other people say that they wrote a novel because they visualized two characters having an argument, and they wanted to find out what the argument was about!
It is common for visual thinkers to visualize scenes as a bystander, but it is also common for them to “see” these things in the first person, as a character participating in the scene.
There is nothing weird or supernatural about being a visual thinker. Oddly enough, there are tons of visual thinkers among the Amish, for whom the retelling of dreams is a major form of entertainment. Saints like Anna Catherine Emmerich and Maria of Agreda, as well as Ignatius of Loyola, were well known for experiencing both strong visual imagination and actual visions. (There’s a good amount of talk in spiritual handbooks, like St. John of the Cross’ Ascent of Mount Carmel and Dark Night of the Soul, about how to distinguish visions from imagination, as well as how to understand real visions from God that take place in the visual centers of one’s head or in one’s imagination, instead of being actually seen with one’s eyes.)
Some visual thinkers have such strong powers of visualization that they also picture things audially, tactilely, etc. They are very creative people.
So basically, I suspect that these “past life memories” are strong visual thoughts and imaginations, very possibly based in part on movies or museums you no longer remember. If you had been raised around other people who had the same kind of creative visual thinking, you would have taken them as perfectly normal and interesting happenings. Since you were hanging around people who were interested in the occult, or perhaps had seen some TV shows about reincarnation, you interpreted the scenes as past lives.
The dark side of visual imagination is that, if someone with strong visual imagination suffers a chemical imbalance in the brain, or a sickness, or psychological problems, or is taking psychological drugs, visual imagination and thinking can sometimes run wild. (And the problem is worse, because some people with strong visual imagination also react oddly to certain drugs, and get bad side effects.) So I have to wonder if this was part of what your mother suffered from. But mental and brain illness doesn’t seem more common among visual thinkers than among the rest of the population.
I hope this helped.