Y not said: “Going down the list of Buddhas antecedent to those 5, the names of the towns and parents and personal attendants etc. of those Buddhas are also Indian-sounding. How is this? How does it come about that previous generations of the solar system produced the same culture(s), not to say the same locations present now?”
This is why the Buddha said not to get into these discussions. It can get very deep, and one could easily spend an entire lifetime thinking about these issues (this belong to “loka visaya” which is one of the “unthinkable” or “acinteyya” subjects); see, “Acinteyya Sutta (AN 4.77)“. English translation there: “Unconjecturable“.
But I assure you that these do have explanations. I don’t want to spend anymore time going deeper. I do understand the curiosity and desire, but these take precious time from more fruitful discussions. However, some of these things will become clear as one proceeds, even without thinking directly about them.
As to the rest of your question: Yes. All those Buddhas were born in this recycled Solar system (Cakkavata in Buddha Dhamma). As a Cakkavata goes through these cycles, the “average gati” of innumerable living beings and hence the Cakkavata that arises have many common features. A Buddha is ALWAYS born in what is called the “Madhya pradesa” close to the equator, in a country that speaks Maghadi (predecessor to Pali), which is the “natural language” of the brahmas in the abhassara brahma realm. A Buddha ALWAYS attains Buddhahood under a special tree (different trees for different Buddhas) that is born at the same time as that Buddha, etc, etc.
And I have already pointed out that science is evolving. Many scientific theories about the universe have changed drastically even during the past 100 years.