Oh, time is enough for you to visit those place. You can also select one day to have a side trip to Macau. I would like to suggest you s simple itinerary:
April 4: Ngong Ping 360 and Disneyland
From the airport, you can take bus S1 to Tung Chung station, then walk to the Ngong Ping 360 Cable Car terminal. After Ngong Ping, you can back to Tung Chung station to take metro Tung Chung line to Sunny Bay and then take the Disneyland Resort.

April 5: Ocean Park, The peak, Wax Museum, Avenue of Stars, the Symphony of lights
You can take MTR from Mongkok to Central, then take bus 6X to the Ocean Park. Then back to the Central to take bus 1 to the Peak. You can see Wax Museum along the peal road. After the Peak, you can back to the Central to take metro to Tsim Sha Tsui and walk to visit the Avenue of Stars. You can also see the Symohony of light there in the evening.

April 6: Take ferry from Tsim Sha Tsui to Macau for one day.

April 7: the Bauhinia Square, Central area. You can take MTR from mongkok to Wan Chai to see the Bauhinia Square.

April 8: Shopping at Mongkok area and Tsim Sha Tsui area.