Esquire has a feature on the history of Ghostbusters, including this bit about the song:
GROSS: They played it ad nauseam. Many people said to me, “I love your movie, but can you get them to stop playing that fucking song on the radio?”
MEDJUCK: I remember friends of mine writing me from Africa, saying that there were people walking around playing “Ghostbusters” on their radios.
REITMAN: About six months later, we heard that Huey Lewis was suing us.
PARKER JR.: There were many lawsuits. When you sell that many records, I think everybody wants to say that they wrote the song.
I’ve never heard the similarities.
Also, my school friends and I did this:
RAMIS: Teachers were writing me saying, “Kids were playing Ghostbusters in playgrounds, and it was very good. It wasn’t about one set of kids versus another like cowboys and Indians. They were working together fighting evil spirits.”
The GI Joe kids kicked our asses.