You have to come back in Free Play for the rest of the collectibles, just like if you want to complete all three Challenges because you can finish only two in Story Mode.
Of course, you should also find Han, which is not that hard. The developers at TT Games usually make the main missions easy; however, getting the Minikits is a different story, not being so straightforward, especially in this case.
So check the guide below to find out precisely what you must do to obtain all five A Plan To Save Han Minikits.
Minikit #1: Trail Of B. Crumbs
At the start of the mission, the first thing you want to do is turn right to find an Astromech Droid Console that you can use with an Astromech Droid like R2-D2.
The console opens the door near it, so proceed through and switch to a Jedi or Dark Side character.
Run on the wall to the right to avoid the first gap.
Jump on the objects in the second gap to pass to the other side.
Now climb the wall in front of you, and you’ll see a small creature running away from you as you proceed forward.
Chase the creature, and you’ll reach an open room.
Here you can see the creature coming out from the ground through some hatches.
Smack the creature until you lower its health bar to zero, then use the pieces you get to create the first A Plan To Save Han Minikit.
Go and collect it so you can continue with the rest.
Minikit #2: Major Malfunction
Now open your map and look for a Key symbol somewhere in the middle. Head to it at the starting area of the mission, and in one of the two structures near the big turret, you can find a Protocol Droid console.
So, switch to C-3PO or any Protocol Droid character and use the console to get the password for Jabba’s Palace Droid Poll Room.
Open the map again and look for the Lock symbol this time.
Go there to find another Protocol Droid console.
Switch to C-3PO again and use the console to input the password you have just obtained.
After a short cutscene, a door near the console opens.
Go through it, and look for an Astromech Droid console to the left.
Switch to R2-D2 and access the console to open the door in front of it.
Enter the newly opened room and use the lever on the left to reveal some pieces that you can use to build A Plan To Save Han Minikit #2.
Hang in there! Three more to go.
Minikit #3: Photogenic
Opposite the small room with Minikit #2, you can find an unfinished painting on the wall (in the right corner).
Find the missing pieces that look like this:
Two pieces are on the left side of the painting, sparkling like the one in the screenshot above, and the third is right in front of the picture, behind some boxes (the latter is the one from the screenshot).
Switch to a Jedi or Dark Side character and use the force to put the pieces back in their place on the painting.
You can now collect the third A Plan To Save Han Minikit that was just revealed.
Minikit #4: Jabba’s Palace Redemption
You can now leave the room that you opened with the Protocol Droid console, and as you exit, look to your right to find an opened room with a box on the left of its entrance.
Enter and go to the back of the room, where you can find a door to the left that you can destroy. But to do that, you have to switch to a Villain character and throw a grenade at that door.
After you breach through, you can collect the next A Plan To Save Han Minikit.
Minikit #5: Max Rebo Band Roadie
Continue your way through the mission until you reach the throne room and find Han in stasis.
Near Han, you can find a power cell that you have to use to break him out of stasis.
Postpone that for a while, but pick up the power cell and turn back to go down the stairs. Then go to the right and find a socket there, like in the following image.
Inset the power cell into the socket to reveal the last A Plan To Save Han Minikit.
Good job! You have collected all five Lego Star Wars Skywalker Saga A Plan To Save Han Minikits. You can now focus on the ones in The Copa-Khetanna.