Mucawiya was chosen because of his administrative skills and leadership qualities but also because of his knowledge of sham.
The bani ummaya were amongs the richest the elite of mecca and they had extensive trade links in al sham.
Mucawiyas family owned several estates in philistine and the jordan valley before islam and they all spent time in damascus , they knew the people .
Mucawiya had contacts in damascus even before he was appointed governer.
The same with Amr ibn al cas with egypt.
He was the only meccan to have travelled externsivly in egypt before islam.
Egypt was not on the trade route and nobody knew it like al sham, but he know how rich it was and the political situation.
I believe Amr Ib Al'A'as is a cousin of Muawiyah, they're from the same Banu Umayya tribe and for that reason he never challenged Muawiyah's leadership. In fact, he was on Muawiyah's side during the First Fitnah. Are the Banu Umayya part of the Quraiysh? Because, I thought the Quraiysh were the elite in Makkah.
Yeah they quraish banu cadnan bau ismacil banu ibrahim from makka. The rest are not arabs like madina aka yathrib they are yemanites/south semitic who migrated to there during the al marib flood. They are called aws and khazraj aka al ansaar. Arabs are nasty people, they explled the prophet from his land that why saudis are nasty except the good madina people.
Between yemen are quraish lived another stand alone clan called al qudaaca some historians said fain tacadnanat fahiya cadnaaniyah wa in taqaxtanat fahiya qaxtaniyah. Looks like the hawiye raac clans of somalia they have been associted mostly with qahtan/yamanites.