@Mademoiselle Kitty >^..^< said

John and George: The last proper meeting between George and John took place in November 1974. A month later, they fell out when John refused to come to the meeting during which the Beatles would officially be dissolved, even though it was very near his home and the others had all flown in for it. Apparently, there was a brief meeting in September 1980, but whether or not this is true and how that meeting went remains obscure.

John and Ringo: Ringo last saw John on 15 November 1980. Unlike the other three, Ringo remained close with all of his former bandmates and visited John regularly. He also managed ‘reunions’ of sorts by getting them all to play on his albums. They all appeared on Rotogravure, released in 1976 although all four of them were never in the same room.  

A couple of corrections (one big, one small), some additional information, and an observation or two.

Apologies, Mademoiselle, but you are wrong on George. Their last meeting took place on the 20th into the 21st December 1974. At least, that is the last fully documented meeting between the two.

The Beatles were gathering in New York to end The Beatles. New York was chosen because John was there, and George had matinee and evening performances at Madison Square Garden on the 19th and 20th December to end Tour ’74. George had even got John to agree to join him on stage for a couple of numbers on the 19th.

I was a bit nervous about going on stage, but I agreed to because it would have been mean of me not to go on with George after I’d gone on with Elton…

How ironic that would have been had it happened: Two ex-Beatles appearing on stage together on the day they had dissolved The Beatles.

So, the date was set for the 19th. Paul flew in from England, Ringo flew in from the West Coast (though probably would have done so to support George at the end of a difficult tour anyway). They gathered at the Plaza, Paul:

There were green-baize tables… like the Geneva Conference it was… with millions of documents laid out for us to sign.

They were all there. John wasn’t. Increasingly angry calls flying his way. Eventually John sent over a balloon with a sign reading, “LISTEN TO THIS BALLOON”!

May Pang:

I remember George calling up, and I said, “Hi, George. Do you want to speak to John yourself?” He says, “NO! GIVE HIM THIS MESSAGE!” He’s screaming through the phone, he’s screaming, “Tell him I started this tour alone and I’ll end it the same way!”

John:

George was furious at the time because I hadn’t signed it when I was supposed to, and somehow or other I was informed I needn’t go to George’s show. I was quite relieved in the end because there wasn’t any time for rehearsal, and I didn’t want it to be a case of just John jumping up and playing a few chords.

For all the, worried about tax implications of the deal for him as the only US resident, or the stars not being in alignment, or whatever, I sometimes wonder if a big part of John’s refusal to sign that day was to get out of going on stage that night. He had to have a rough idea of how George would react. He had thrown a similar, but different, hand-grenade into his appearance at The Concert for Bangla-Desh. Just an interesting coincidence or John knowing what buttons to press?

Anyway, 20th, Julian was taken to see George’s show, while John had a meeting with Lee Eastman, who was attempting to get him to sign.

May:

We were at the Eastman’s, and Lee was trying to convince John to sign the papers. He was telling him, “This is all your fault, that’s why George hates you. He never wants to speak to you again. And then a phone call came in and it was Julian, he said, “I just saw George and he has a message for dad.” I relayed the message to John: “That was Julian and he has a message from George for you. He says all is forgiven and wants you to come to the after party” John turned and said, “Well Lee, I guess the meeting’s over.”

John and May did attend George’s end-of-tour party at the Hippopotamus club that night. Yoko also attended separately.

Rolling Stone:

John and George left together in the wee hours and headed straight to the Plaza Hotel, where they room hopped and talked past noon the following day.

At the Plaza, George had agreed to do an interview with KHJ Los Angeles radio. Most of the interview is just with George, but these few minutes have John in the room:

Ringo’s Rotogravure featured songs by all four Beatles, but appearances by only three. George gave Ringo permission to record his unused When Every Song Is Sung and rename it I’ll Still Love You, but he couldn’t make the session because he was trying to complete 33&1/3 on time. The lead guitarist on Ringo’s version is Lon Van Eaton (formerly signed to Apple).

Ringo and John’s last meeting took place at the Plaza:

I hadn’t seen him for a while… we see each other where ever we are, and he came over with Yoko for an hour, and we had such a great time ’cause they stayed five hours. And it didn’t matter it was a year between we didn’t see each other; it was always fine when we did. But it was a particularly great time that we, that I had anyway.

Should 21 December 1974 be the last time John and George were together, then it’s one of those weird coincidences that the last moments John got to spend with two of his small band of brothers was the very hotel which had been their base camp all those years before when they first arrived in the land of Rock and Roll, to change it forever.

It wasn’t intended as a criticism, @Mademoiselle Kitty >^..^<. The suggestion that George and John fell out over John’s no-show at the dissolution meeting and George never saw John again as a result (apart from a rumoured encounter in September 1980 which is of questionable provenance) creates a false impression of what happened though. Yes, George was furious with John when he wouldn’t sign the papers on the 19th, but it wasn’t the fatal rift in their relationship you indicate. All was forgiven within 24 hours, and John spent that night and half of the 21st with George, including recording in the wee hours of the 21st what may well be the final interview to feature more than one Beatle while they were still four.

Your suggestion creates the impression they parted ways on bad terms and never saw each other again, whereas they seem to have parted ways on good terms and kept in touch, after a fashion. As George would tell Rolling Stone on 19 February 1979:

I get post cards from him – it sounds like the Rutles, but he keeps in touch with tapping on the table and post cards.

They were fine with each other after the non-signing debacle. What proved to be the final break between John and George came in July 1980 when John read George’s book I Me Mine . It’s also what makes the September 1980 encounter questionable for me. The Playboy interview was conducted over much of September 1980. On and off between the 10th and the 28th.

During those interviews, John made this comment on George and his book:

I was hurt by it. By glaring omission in the book, my influence on his life is absolutely zilch and nil. Not mentioned. In his book, which is purportedly this clarity of vision of each song he wrote and its influences, he remembers every two-bit sax player or guitarist he met in subsequent years, yet I’m not in the book.

I am sure that had John run into George sometime around then, he’d be telling the press about how he’d put George in his place over his annoyance at his lack of mentions in the book. That’s who John was. He was telling the story about telling Paul to stop just turning up on the doorstep with his guitar.

The order things happen is important when you have a large cast and a complicated script. To me, the big mistake was not November, but the suggestion that John’s no-show at D-Day (Dissolution Day) ended their ability to be in the same room.