Thank you R. I can't draw on experience to formulate views as to how the oversoul works. Don't think that an incarnation following completion of the oversoul (but that's only me speculating) would be some sort of super human with 100% conscious recall of the collective wisdom and experience though.

Tibetan Rinpoches (who have vowed to be reborn until all beings in this reality achieve realisation) will if pushed however sometimes admit to the ability to access information from past lives, and on just about all shades of existence. (they may embody differing levels of realisation)

Some of the more realised (bearing in mind that it's not regarded as good practice to talk too much about this stuff or to flout it as it creates the wrong perspective)  demonstrate pretty amazing abilities to know and to influence events and their own physical reality - beginning from childhood. Some pretty amazing stories of very odd events are told by those that accompanied the 16th Kagyu Karmapa (hope I have the number right - he died in Boston back in the 80s) on his US visits.

On the other hand they have to be brought up and educated the same as anybody else - if something comes through it seems to be in the form of insight, intuition, wisdom, compassion and the like plus special abilities. Whatever else these traditions have an amazing track record in picking kids at a very early age, declaring them a reincarnation of whoever. The deceased has usually left information so that he can be found when he is reborn. (which implies control over this too)

They almost without fail blossom into the most amazing individuals as above....

Whatever about the above, I have to agree to wondering too how the bodhisattva vow when (as is usually the case) taken by a single not very realised individual can be a good idea. Unless of course there's something slightly magical going on....

Good thinking R. Not only that but the highly focused creative intention created by a highly disciplined meditative tradition would make it especially likely that it would play out to script.

Gets really interesting then though, in the that it really does blur the boundaries as regards the personal perspective on reincarnation and on what it is that actually has continuity between lives.

It's definitely not total the personality or the body, maybe something more like a set of attributes and tendencies that interact with the biology and the circumstances it finds itself in....