All of these questions about rebirth lately focus on what happens at the end of life. The questions themselves betray confusion and I would suggest to help clear it up first focus on a narrower investigation.
Here is an important fact that should be kept in mind whenever trying to understand rebirth:
The Buddha taught that sentient beings are reborn moment-to-moment in this very life.
This cannot be emphasized enough it seems! We are reborn continuously in every moment in this very life. Before devoting attention and effort to understanding how we are reborn from life-to-life... first devote attention and effort to this! How is this possible and what does it mean to be reborn from moment-to-moment?
The reason I emphasize this is because people seem to acknowledge this teaching by the Buddha, but think it easy to understand and simple to comprehend. I would suggest that this is not so true... why? Because of another fact that should be kept in mind:
There is no difference in kind, manner, or extent between the rebirth we experience moment-to-moment and the rebirth we experience life-to-life.
If you truly understand one, then you necessarily understand the other. They are the exact same phenomenon. Which leads me to suggest that those who profess to understand how we are reborn moment-to-moment, but are still confused how we are reborn life-to-life... well, this indicates they don’t actually understand what it means to be reborn moment-to-moment!
So I say keep investigating moment-to-moment rebirth... you’ll know you’ve come to a correct understanding when there is harmony and agreement between rebirth moment-to-moment and life-to-life. When there isn’t a scintilla of difference you can see between them.
Hope this helps!
With this in mind, let's see what happens when we transform your questions to consider rebirth from moment-to-moment.
"If one says that the next rebirth would depend on the degree of identification, does that mean that if I am not identified with body I will be reborn without a body or as mind only?"
Have you succeeded in this very life with not identifying with your body? In this very life, are there moments where you are reborn with no body or as mind only? This is an empirical question you can answer yourself! What happens when you are dreaming? What kind of body do you have? Do you experience a formless dream with no dream body? What about deep meditation... have you experienced a formless realm?
Or does it just go to a higher being overall that keeps that degree of overall identification and not restart from scratch? Or the rebirth just restarts all the identifications and the path has to start all over again?
Again, ask yourself what happens in this very life when you are reborn moment-to-moment. In that context, I am not sure how to interpret your question(s) here. If you cannot interpret your question with regard to rebirth from moment-to-moment I would suggest the underlying assumptions of the question(s) are flawed. Can you interpret them?
What also caught my attention is if there is complete dis-identification even with the inherit "I" self existing independently, and that now existence itself realized that it is not this limited "I" because it can't be that "I" realized but what is before that which is nothing and everything and no birth will occur, doesn't that mean "I" will never exist again and just dissolve into non-existence? Or rebirth can happen as a completely dis-identified being by default?
Did the Buddha just disappear when he achieved nirvana beneath the Bodhi tree? Do Arhats just wink out of existence when they achieve nirvana? Do we see spontaneous combustion or beings just up and poof disappearing on their prayer rugs while meditating? I don't see this. Do you?
No, what happens is that conventionally existing things continue to exist conventionally just as they did before and not one whit more. They begin and end conventionally just as they did before and not one whit more. All of this is like a mirage, like a dream, like a flash of lightning... impermanent, phantasmagorical, effervescent, insubstantial, existing only like Theseus' boat without any true existence whatsoever! Nothing truly real ever began or will ever truly end because nothing truly real has ever existed in the first place!