I do think McCartney was more interested in sounds outside of the rock n roll realm than Lennon was in the early days. It was McCartney that introduced classical music to the Beatles and was obviously quite influenced by George Martin. Lennon was more of a straight rock n roll guy who could write great lyrics. His big influence before Yoko would have been Bob Dylan. I don't think either would have been familiar with Varese of Schaffer (I haven't heard of them myself to be honest), I think Revolution 9 was certainly influenced by Yoko's avant-garde leanings. At least she didn't do one of her patented screams
.