USB Type C Host PORTS PD Controllers
In Host PC that have USB Type C Ports is it correct to assume that
  they will be implemented with PD controllers


No, it is not correct to assume that every Type-C port uses PD - power delivery specifications. Power Delivery is independent and optional feature.


  
  Use the CC lines to decide whether to provide VBUS (and in the worse
  case may even not provide VBUS power) ?
  


This is the standard function of a Type-C port. No need for PD here.


  
  Once proper validation with the device connected then will be able to
  provide +5V upto 3A on the VBUS lines ?
  


Again, this is the standard function of a Type-C port, no Power Delivery is necessary. If the port carries the USB host function and is designed to drive up to 3 A power, it should "advertise" this capability by having 10k pullups on CC lines. If the port can source only 1.5 A, it should have 22k pull-up. If there is enough power only for 500 mA, the port should have 56k pull-up to 5V. A simple voltage comparator of device side is sufficient to determine source port power capability. The PD (or its subset) is required only if 5 A is designed in, or higher voltages are used.