> Of course he got it from the cemetery. The idea that he coincidentally landed on the name ‘Eleanor Rigby’ - for a song about a woman who “died in the church and was buried along with her name” - is wildly implausible.

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> (Note that the gravestone in question isn’t even for Eleanor Rigby herself but her grandfather; her name is further down, a detail).

So, in any case he didn't name the character after someone who died in the church, or was even buried there, but someone whose name appears there. Essentially, the connection is that the name Eleanor Rigby is engraved in a place where Paul McCartney has been before. The fact that he met Lennon there does not mean that the place is seared in his memory, it just means it's of historic importance to Beatles fans, which may be making this coincidence seem like something else.