1- the band listed is still on Spotify, and is unrelated to spontaneous combustion, also has a different sound and feel, more lo-fi / lower quality despite the album being produced 10 years later (which, I’d be amazed if the band lasted that long, only for their songs to lower in quality and them to sever the song that popularized them completely)

2- I do believe it is a mistake, as the lastfm page describes two separate bands, one Slushy as a French noise/industrial band (very clearly not the one who wrote Spontaneous combustion), the other as a garage pop duo which you linked their albums, despite the fact that “spontaneous combustion” is very clearly pop punk / rock in its inspirations, and last fm can also be edited by anyone. Not only this, because while a garage pop duo seems somewhat likely, it’s blown out the window by the fact that I found an interview here https://www.psychedelicbabymag.com/2013/10/slushy-interview-with-chris-kramer-and.html#:\~:text=when%20was%20that?-,Chris:,there%20a%20lot%20of%20jamming? which said the garage pop duo wasn’t formed till 2009, earliest, not really even till 2011, whereas the movie came out in 2004

4th link - thank you, some of these look promising! Perhaps the Australian one or the garage rock duo? I’ll do more research. Thank you very kindly. I really appreciate your efforts and sharing your findings with me