In my iOS app, I just need to find out the beacon region entry/exit based on the UUID, Major, Minor numbers. The beacon I am going to listen for can be of any type say Estimote or an iOS device which can act as a beacon. Can I use CoreLocation alone for this scenario or I have to use Estimote iOS SDK for detecting Estimote beacons and CoreLocation for others?
You can use CoreLocation to work with any iBeacon. Estimote SDK adds some additional functionality on top of CoreLocation but it is not required to work with Estimote Beacons. CoreLocation will discover them.