She was the product of many generations of incest, and did have Egyptian blood(some of the Ptolomies has liasons with local egyptians) though the statue/coins make her look just slightly better than plain. Children of Incest that were not all there were routinely killed. Egypt was a wealthy realm, every roman leader desired the loot for themselves and Cleopatra was trying to maintain her rule and independance of her kingdom. Unfortunately she bet on the losing side. The best treatment of her that I have found is in
FROM ALEXANDER TO ACTIUM by Green. It will answer all your questions, and some that you have not thought of. as I recollect, she spoke many languages.