I’ve always wanted a thread like this, now I know it exits!
I, like many others on this thread, thought that the Death Star II was the remains of the first one.
Since I loved the Muppets before I knew what Star Wars was, I thought that Yoda was straight out of the Muppet show since my mum had told me he was voiced by the same guy as Fozzie Bear.
I thought that when Zev Senesca (Rogue 2) was shot down by an AT-AT, it was actually Wedge and he had just died, so I had no idea how Wedge was alive in ROTJ!
And finally, here’s a weird one:
I have a specific memory of a scene in ROTJ where Salacious Crumb is chewing on Jabba’s tail and bites a chunk out of it. I know, sounds awful, I have no idea why I remember this, seeing that it never happened but I always thought as a kid that he started eating Jabba!