I remember I was really confused about if Farfetch'd and Doduo was related by evo or not. I mean, they were beside eachother in the dex, had similar colors, were both birds but yet.. looked so different haha. I also thought Dunsparce evolved into Gligar, and that Latios/Latias was somehow related to Lugia.
I also remember I had a hard time believing Politoed was an alternate evolution of Poliwhirl.
When I was young, I thought Farfetch'd evolved into Doduo and then into Dodrio. I think this was because they were next to each other in the pokedex and because I collected the stickers/sticker album, and in that pokemon who evolve into each other had "joined" stickers (I can't think of another way to describe it) and Farfetch'd's sticker was joined to Doduo's... Silly people who made it misleading me.
The first time I saw a poster with the first 151 (I was about 9 years old) I thought there was a connection between Gengar and Cloyster!
Also, I believe Luvdisc and Alomomola were a planned evolution but cut because Generation V didn't have any connection to passed generations. Perhaps there will be a middle evolution to connect them at one point.
Until knowing of Blissey I thought that Chansey evolved into Kangaskhan.
Think about it. Egg-shaped thing keeping an egg in its pouch --> Dinosaur-shaped thing keeping a baby dinosaur in its pouch.
Also Farfetch'd --> Doduo, but that was because of their placement in the pokédex and that Doduo looked to me like a middle-stage back then.