Bismillah ArRahman ArRaheem
1. We have in narrations (for example under Tafseer Qummi, under 2:127 And when Abraham, and Ishmael with him, raised up the foundations of the House: 'Our Lord, receive this from us; Thou art the All-hearing, the All-knowing;) that Kaaba came was sent down with Adam peace be upon him, so it was there from the start of mankind, and was lifted at the time of the great floods (time of Prophet Noah peace be upon him). Prophet, peace be upon him and his Purified Household, Ibrahim, peace be upon him, rebuilt the house rather than having built it as a new project! Archangel Jibrael peace be upon him, showed him the parameters of the house and where the bricks should be laid and it had two doors.
2. With regards to "qiblat", that was not a "change of mind" but rather a part of history that was already part of the plan to show the Children of Israel that Muslims have their own Qiblat. The jews would mock the Prophet, peace be upon him and his Purified Household, having to pray towards Al-Aqsa and so the direction was then changed in order to separate their Qiblat from the muslims, this was an important material and spiritual change for the muslims of that time and continues to be. See exegesis of 2:144. Also in Tafsir Al Mizan you will find an explanation that says that Al Aqsa was not the first direction in which people would worship towards but was in fact Mecca (Ibrahim and Ismail, Peace Be Upon Them, (re)built it and called for the hajj since then, See Ibrahim: 37, Hajj:27, Baqarra:125.).
3. "Bebak" comes from the place in which place will crowd and be really close to each other as they perform the tawaaf (as in pilgrimage). From the time that ayah was revealed till now people refer to the Ka'aba as the centre of hajj rituals intuitively - ie their mind immediately goes there when that word is mentioned in that context and in that ayah, ie it is synonymous with the city of Mecca. So there is no doubt that the ayah refers to Mecca.
4. No, it was not chosen for commercial value. People deviated and worshipping took a turn for the worst and people started to worship idols there. That is part of the history of the place and commercialisation was a form of making a living not the reason for it being chosen as the epicentre of worship (being in the middle of desert and hard to access makes it an unlikely location for commercial reasons, and while they pocket their billions, they struggle with the location).
5. Google results does not make something a fact. And greeks not having written about it does not make it non existent.
6. Saudi Arabia has been destroying facts and historical places for many years now in the hope of destroying any evidence it has which may point against it, (house of the Prophet, peace be upon him and his Purified Household, Khandaq, the houses in medina, not being allowed to visit certain places including Baqee, the destruction of the Baqee in Medinah etc). This has been going on for centuries and in fact since the umayyads and the abbasids with their fabrications of history and insertions of narrations, and quite honestly even before then, and that still continues to this day (search the crack in the Ka'aba, why it is there, and who often they try to fix it but can not). There is definitely something there they do not want us to know. But the truth will always prevail, Insha-Allah.
We hope this guides you and the readers, as well as myself, to the right direction. These are certainly thought provoking questions. Well done and all the best.