You did the major things but did u try to check the two cooling fans?
They could be one of the reasons for the overheating.
To check the fan is very easy just when the car is off try to rotate it by ur hand, if it is rotating smoothely it mean the fan is not working fine but if it is rotating hard then it should be ok.
Also , the follwing things could cause overheating in the car ,
1 - low level of oil could cause this problem.
2 - Air filter if dirty , it cause this problem.
3 - Radioator top cap is very critical, it should automatically release when the pressure reach 90 kpa , double check the seal in the cap and press the spring in the cover and check how easy it is .