I've always thought that Neubauten were likely influenced by some of Can's more rhythmic stuff (I'm thinking particularly some of the tribal influenced beats on Tago Mago). Kraftwerk is also a very likely direct ancestor (while their
"Autobahn" is not exactly a cover of the Kraftwerk song, it is certainly on some level a tribute or at least a comment on it).
They were also very clearly influenced by the Dada art movement in general and by a lot of avant garde music that wasn't connected to the pop music world that they somehow invaded through post punk. In paticular
Stockhausen and
the Futurists (the turn of the 20th Century Italian ancestors of all industrial and noise music!), and also likely
Harry Partch. I'm just making an educated guess, but I'd think Cr@ss had to be one of EN's most direct punk rock ancestors.
Neu! like most of the Krautrock bands also drew influences directly from non-popular music forms, specifically avant garde clasical, but also jazz, and eastern music. Nonetheless, I don't think they would ever have been playing rock based music at all if it weren't for the '60 psychedelic music, and the Velvet Underground. When they split from Kraftwerk and called themselves Neu! that was a deliberate pop art reference that certainly brings to mind the VU/Warhol connection.
So yeah, nothing exists in a vacuum. The most original experimenters in rock usually lift from other genres to be more original (Jello Biafra details pretty thoroughly in RE/Search's Incredibly Strange Music how a lot of DK's music was based on obscure lounge records from the '50s!)