On October 19 1967, The Beatles were continuing on the development of "Hello Goodbye" in Studio 1 at EMI on Abbey Road. The overdubs completed on this day was some lead guitar by George Harrison and the main vocals by Paul McCartney. There were also counterpoint vocals added as well as the coda vocals during the "Hey - La, Hey -Ba-Hello-Wa" segment. This was considered take 16 and was later released officially in this early form on the Apple 3-LP/2-CD "Anthology 2" project. You can hear some lead guitar bits that were eventually scrapped as this take 16 was "reduced" on the four track (combining tracks 3 and 4 of the vocals) to create take 17. The song stood in this form at the end of this session.
The next day on October 20 1967, violas were added to the middle part of the song as well as an echo laden vocal for the "Why why why" section of the song by Paul. This was once again reduced with both the guitar track and viola tracks combined - Paul added his bass to the remaining empty track and the recording of the song was basically completed.
The mixes for the song were attempted and completed on November 02 1967 with at least six mono attempts and at least two stereo attempts. Thus, remix 6 for mono and remix 2 for stereo. The mono mix can be found on the original Parlophone/Capitol single. The stereo mix can be found on the "Magical Mystery Tour" LP as well as the Apple double LP/double CD "1967-1970" and the original mixes of Apple's double LP/CD "Beatles 1" project.