There's just happen to exist proven impssible things in the world

[lavantien]

Just as the universe/multi-verse can't produce green star, regardless of the cosmic constant, so too, there is thing that impossible just as the Buddha mentioned. Such as, it's impossible for two Budddha can appear at the same time. Or, it's impossible for a stream-entrant to take an 8th rebirth.

https://suttacentral.net/an10.21

The Realized One possesses ten powers of a Realized One. With these he claims the bull’s place, roars his lion’s roar in the assemblies, and turns the holy wheel. What ten? Firstly, the Realized One truly understands the possible as possible and the impossible as impossible. Since he truly understands this, this is a power of the Realized One. Relying on this he claims the bull’s place, roars his lion’s roar in the assemblies, and turns the holy wheel.

https://suttacentral.net/mn115

They understand: ‘It’s impossible for two perfected ones, fully awakened Buddhas to arise in the world at the same time. But it is possible for just one perfected one, a fully awakened Buddha, to arise in the world.’ They understand: ‘It’s impossible for two wheel-turning monarchs to arise in the world at the same time. But it is possible for just one wheel-turning monarch to arise in the world.’

They understand: ‘It’s impossible for a woman to be a perfected one, a fully awakened Buddha. But it is possible for a man to be a perfected one, a fully awakened Buddha.’ They understand: ‘It’s impossible for a woman to be a wheel-turning monarch. But it is possible for a man to be a wheel-turning monarch.’ They understand: ‘It’s impossible for a woman to perform the role of Sakka, Māra, or Brahmā. But it is possible for a man to perform the role of Sakka, Māra, or Brahmā.’

[SarathW]

There still could be a Pacceka Buddha.
Seven life is the minimum for Sotapanna does not mean he will have another life. Perhaps these seven lives may not be literal. What it means is you can attain Nibbana in a very short period.

[lavantien]

There still could be a Pacceka Buddha.

According to the Theravada view, a Pacceka Buddha cannot arise in a time where there is still a dispensation of a Buddha going on.

Seven life is the minimum for Sotapanna does not mean he will have another life. Perhaps these seven lives may not be literal. What it means is you can attain Nibbana in a very short period.

When you flip the switch of re-intepretation like that, where will be the stopping point? Does Buddha Dhamma can still be recognizable?

https://suttacentral.net/an2.21-31

“Mendicants, these two misrepresent the Realized One. What two? One who explains a discourse in need of interpretation as a discourse whose meaning is explicit. And one who explains a discourse whose meaning is explicit as a discourse in need of interpretation. These two misrepresent the Realized One.”

[SarathW]

When you flip the switch of re-interpretation like that, where will be the stopping point? Does Buddha Dhamma can still be recognizable?

As far as I know, there is no real logic of seven lives except seven fetters to be eliminated to become an Arahant.
Perhaps this could be a symbol for the seven fetters left.

[confusedlayman]

Seven life is seven life.. buddha spoke in conventional way using language