All Collectibles in order as they appear. The characters used are just examples. Of course, you can use whatever character you like with the according abilities ;-) :
Part A: Castle Corridors
Use the dark force on the big gate to the right and cut it open with the lightsaber.
Open the bedroom to the left with the force. Destroy everything and use the bricks to build a device for BB8 in the center.
Repair 3 statues with the force
Outside, use Ackbar at the pool (unlock him at the "Poe to the Rescue" mission)
Story related, after you go up through the hatch, there is an area to scan at the back. Blow up the box with Silver Lego blowup.
Open the cracked Lego box.
Remove the Tie Wing with the force and send Ackbar for a dive.
Pull open the double grapple box
Part B: Takodana Skies
Shoot 4 targets on the water
On top of the ruins
Shoot 3 towers with pink bombs. Wait for the last phase of the battle for ties with bombs to arrive.