I merged A Bug's Life, Antz and The Ant Bully in my head for a brief period as a kid.
Yeah especially with Antz and a Bug's Life, really only animation aficionados seem to know that there are 2 different studios involved, and that they aren't the same movie. Heck, I can remember playing part of A Bug's Life in youth group for a lesson and among the first comments was: "Antz, right?" (haha) 2006 was a WILD year for computer animation, I could imagine that people mixed a lot of movies under the wrong studios since everyone was cranking out computer animated movies that year (seriously, it was SO common that some national newspaper even did a story on it). Sort of like all the people who thought that Anastasia was a Disney movie, it had full influence of Disney, but it definitely wasn't (reportedly some overseas Disney Channels aired Warner Bros and/or Fox Studio products which did add to the confusion) and I am pretty sure I knew this from the beginning. Sort of felt like I was the odd one out for knowing that Anastasia wasn't Disney.
Well, I remember when I first saw Sandybell as a kid, I thought it was Candy Candy because they were both about a blonde girl with an animal companion and that they had similar stories before I realized her name was Sandybell and that I had managed to catch more episodes of Candy Candy later on the same channel though.
Yeah you would be forgiven as a fair amount of older shoujo sort of has the same "sparkly doll eyed, fluffy hair" protagonists, with many blondes in the mix. I have developed an "on and off" interest in older shoujo, and I keep having to check and recheck names since I mix a lot of them up together, not to mention that many of them don't have official English titles.
Maybe it's because they all have similar titles/vibes but: The Watcher in the Woods, Something Wicked this Way Comes and (a little bit) Escape to Witch Mountain (that last one is likely just because of "witch" in the title). They are all also connected with Disney in some way.
Also, I honestly believed that the song Hella Good (better known as Keep On Dancing) by Gwen Stefani/No Doubt actually utilized a Mario Bowser theme, but never found any connection between the two.
I just remembered that I used to sometimes mistake Neil Patrick Harris for English actor, comedian, radio personality, television presenter and singer, Alexander Armstrong. When I went to see A Million Ways to Die in the West, I thought Foy was played by Alexander Armstrong until I found out it was Neil Patrick Harris.