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 Approach
Hunt 9 rats.
Open the cracked Lego wall
Destroy the tree and use Ackbar
(Unlock Ackbar at the "Poe to the Rescue" Extra Mission)
Scan the tower, pull it down with grapple and build a device to the left that removes the tree. Now climb up to the balcony. (All Story related)
From the same balcony, hover over to the next one.
At this balcony, go through the hatch
Back on the ground. Shoot the red button on the wall to the left.
Part C: Castle Basement
In the basement go back up the stairs
Shoot 4 cobwebs
Use someone with Silver Lego to blow up the wall, go into the room.
Use the force to open the door in the main room