You can probably find books and other data on these subjects. I believe that we have guides, including our Higher Selfs, to help us decide who to reincarnate as. Teachings I've heard indicate that it takes at least 30 years to reincarnate.
But I also understand that many of of us don't wait 30 years and reincarnate significantly sooner. For me, I believe it took less than 11 years to reincarnate, since my last lifetime.
Some of us don't want to wait that long to reincarnate. At the end of this Age, the Kali Yuga, as advanced souls, we can choose to reincarnate sooner, so we can learn as much as we can before the end of this Age, which is upon us.
I recall reading of a particular race or group, that believed that they would reincarnate quickly after death. You may be an example of that yourself, even though you may not have been part of that group, or had that belief.
If people have that belief, then it may be their particular way of doing things, natural and normal to them. More advanced souls can also sometimes live simultaneous lives, living two or more physical lifetimes.
Reasons that people would reincarnate more quickly or live simultaneous lives, whether one would be aware of living simultaneous lives or not, would be to learn lessons more quickly and to have a greater positive impact.
An example of someone who immediately reincarnated, is Stewart Swerdlow, who wrote about his experience in a book published by Preston Nichols and Peter Moon in Sky Books.
Peter Moon may still be living. He'd be about my age, 72. You might be able contact him to buy a copy of that book, once you find out the Title, which I don't remember.
Stewart Swerdlow wrote that he had been a Nazi Officer, during WWII, who was somehow included in the Philadelphia Experiment, August 12, 1943, with the U.S. Navy sailors.
Supposedly, the idea was to make the ship invisible to radar, which technology could be used in wartime. The U.S.Navy Cameron brothers were in charge of turning on and off the apparatus, that was supposed to make the U.S.S. Eldridge, invisible to radar.
There was chaos aboard ship, when the apparatus was turned on. Some men's bodies became partially merged in the metal of the ship. And some kind of electronic fire was affecting some of the men. Seeing this chaos, the Cameron brothers tried to turn off the apparatus, but were unable to do so.
The Cameron brothers jumped overboard together, intending to swim ashore and get help. It turned into a Time Travel experience instead. It was like they were falling down a deep elevator. Instead of landing in the ocean, they landed in the secretive military base in Montauk, precisely 40 years in the future parts of the Time Streams.
Many years ago, I heard Al Bielek, at one of the New Life Expos, at the New Yorker hotel. He claimed to have been one of those Cameron brothers and told his story.
In Stewart Swerdlow's case, he wrote that he jumped overboard, from the Eldridge, and also had a Time Travel experience, landing 20 years in the future, in 1963. Tall Sirian extraterrestrials took possession of him and put him in an electric chair.
The Sirians told him that Germany had lost the war, Hitler was gone, they would send him to a more appropriate location and electrocuted him.
Floating out of his physical body, an angel met him immediately and told him it was time to reincarnate and he became Stewart Swerdlow.
I imagine that all these events had been planned ahead of time, before the Nazi officer had been born.
The more advanced we are, the more choice we have in our reincarnations. I believe that before we are born, many of us have a choice of a number of people that we could reincarnate as and we have to decide. Perhaps you planned two consecutive lifetimes, ahead of time.
I've also heard the idea that a certain group had that after they died, they should start looking for a maternity hospital or wherever to find women going to have babies, so they could merge and soon be born again. It sounds kind of unsophisticated to me.
I'm aware that we frequently reincarnate amongst people known to us in previous lifetimes, whether those were friendly relationships or not.
We can even have family members, friends and acquaintances, who were our worst enemies in previous lifetimes. God and life often give us the chance to overcome our differences.
I knew a happily married couple, in Forked River, with children and grandchildren. But hundreds of years ago, she had been an Aztec or Incan priest, who sacrificed him, cutting his heart out. Apparently, she came to greatly regret this and was treating his heart much more lovingly in this lifetime. They and others were aware of all this.