- I never stated that Madara was the founder. You're also gonna have to look back into it further.
- Konoha was created when the union of Senju and Uchiha formed and made a pact with the Land of Fire.
So how was the Hyuuga there before Konoha even existed? Magic?
- The sage was the first known wielder of Jutsu and ninja techniques, so before the sage there was no real ninja families, just endless fighting like Jiraiya stated. After the sage spreaded ninjutsu around, the world of ninja existed. As you stated, there isn't any confirmation about the Uchiha or Senju being the first, just that they were decendants of the two sons. However, the fact that their bloodlines were passed and didn't dilute into something different tells us that they have a pureblood connection to the two sons. The Byakugan however, has no such connection at all.
Also, there is no proof or even hints that the Uzumaki clan is older. The reason why they have such attributions is only because they have a deep history together.
The first country that adopted the 1 village/1 country rule was the land of fire, created by the Senju/Uchiha pack. Afterwords other villages, such as the Land of Whirlpools began mimicking the same thing. So in other words, unless we know more about the history of the Uzumaki and Senjuu, who the creator's were, which Kishimoto will doubtfully write about, this is all in the dark about who's older.