A reader question in the comments brought about an answer too long for that page, in my opinion.
RQ: So would this be mainly back-to-back incarnations in the same family, to continue a task started but not finished with the souls left behind in the flesh, so to speak?
C: It can be, but no, the sequence does not have to be, or is not required to be, or isn’t scheduled the way you describe, for the majority of instances which might be included in what the question describes.
RQ: For example, the great grandfather that comes back as his great grandson, like e.g. died in 2018 and born again in 2021?
C: This is possible and has been done.
RQ: Or could there even be overlaps such as being born e.g. only five months after one’s death?
C: Overlaps are not possible for humans but yes in Heaven.
RQ: What would that mean for the baby in the mother’s womb, would there be a soul holding the place while waiting for the other soul to leave the dying body and be free to take its place in the new body?
C: In Heaven babies do not exist, because humans do not exist. Time does not exist; a soul is not able to wait, because doing so requires the passage of time. Time does not exist; it is an Earth surface illusion.
For the purpose of answering your question, no; no soul is obligated to wait for anything where time does not exist. The human body is subject to time, therefore souls who wish to use a human body become subject to the restrictions and limitations time creates. Souls can leave a body and have another soul enter and take over the life contract, although rare, but any soul can enter any body not occupied or used by another soul, with permission of all souls involved.
This is easy to do mechanically, because your soul departs your body nearly every time you sleep, and almost one hundred percent of the time you sleep for many hours, such as overnight.
The process of departure and return, for sleeping overnight, is no more easy or difficult physically than final soul departure, or first entry. Allow us a comparison; it is physically no more easy or difficult to shoot a water pistol into the face of the prime minister during a meeting of government ministers, than to shoot the water stream into the face of one’s friend during a party. Knowledge of circumstances and consequences matter greatly.
RQ: And if either of these two options in the example were possible, what would that mean for the soul of the great grandfather, would it still be there for the souls of the other older family members when they return home or even during their lifetimes, as support from the other side of the veil, so to speak?
C: We shall speak to incarnation from the perspective of Heaven and your soul, explaining again what we have already done, as some readers might recall.
We ask that you envision the spoked wheel of a bicycle. Each spoke represents a sequence of events in which a soul participates. This wheel has thousands of spokes, and one of them, possibly two, are incarnations in a certain place or upon a certain planet.
The spokes are often connected by small segments attached to two or more, which run perpendicular to the spokes. These small pieces are human life contracts and experiences.
You may create a life agreement, and place another small segment of either a spoke, or a connecting piece attached to both running between them.
You can approach and review any one of these pieces, and you can look at the spoke from the wheel center or from the outer rim towards the center hub.
The spokes and segments between them represent Earth time, which for you on the surface of your planet, are fixed, permanent and always progressing in the same direction.
Your soul neither has nor needs such restrictions; time does not exist for your soul.
Incarnation can be planned and carried out just as your example postulates, or in any other combination, always subject to the limits a human body and the Earth surface environment place upon a body.
RQ: Hope these questions make sense, but I have often wondered about that.
C: Do you hope to say that you would like the questions to generate answers you will like, or with which you will agree? Making sense as humans say these words, often means that. How much or little sense we have made turns on your interpretation of our replies.
Overall, what we wish to say is, souls cannot create a body without agreement from two other souls who agree to be parents and perform the biological function or process to create the body the incoming soul will occupy.
Two souls may inhabit the same body, but this is never done against the will of the one soul or the other. Humans call this schizophrenia or multiple personality disorder. It is uncommon because of the freedom from time constraints makes it unnecessary.
Your soul can incarnate in the Earth's Roman Empire, or during Atlantis, or two thousand years from now and in any order. The human sequence does not apply away from or off Earth. This ease of placement makes the purpose of dual or triple occupation of a body meaningless, unless all souls involved, all incarnated family for example, agree to do it because a specific and beneficial task, lesson and mission will result, which could not be done otherwise."