I’ve been wondering about how to have an onscreen reveal of Vader learning Luke’s identity in ESB and I think it might be possible if you repurpose the Admiral Ozzel Force Choke call into one between Vader & Boba Fett.

(Since I’m using a foreign language dub for my edit I’m working without the spoken-words-matching-meaning constraint but since my plan involves two characters wearing full-face masks, I think a lot of this could still apply.)

Mockup to come, but here’s how I’d tackle it at the start of ESB:

Pan down on Executor and Vader in chamber as General Veers leaves and he turns to make call.
Tune in on Fett taking the call, as good of a straight-on head shot as possible. (If you could have him in the Slave 1 pilot seat, that would be better.)
Vader asks for his report.
Fett says he’s still looking but he has found a name for the boy: Skywalker.
Silent beat on Vader.
Fett says Vader?
Vader says continue your search.
Fett signs off As you wish. Hangs up.
Vader spins back around.
Vader walking to the bridge window.
Vader looks out & says Skywalker.

Along with this I would tweak the crawl to change ‘young Skywalker’ to ‘the young pilot’. And I would not have Palpatine say Skywalker’s name specifically in his Skype with Vader, so the Emperor just knows this Rebel kid is powerful & dangerous and wants Vader to kill him.

If you didn’t know Vader was Skywalker, Fett’s info could just be a shock to Vader that the Jedi he killed had a kid and his later deflection of Palpatine’s order could be read as just serving his master.

If you do know he’s Luke’s father, you get to see his shock at finding out he has a son (and that Palpatine lied to him if you’d seen ROTS) and could be seen in hindsight as the start of him hatching an actual plan to use Luke for his revenge on Palpatine.

Plus it kinda makes Fett stand out a little more as Vader’s bounty hunter of choice.