You're conflating some events here. Just to clarify:
Too, (and this is so minor) the company was originally called Wentworth Industries, not Barnes Global. Cliff's mom married Herbert Wentworth and when he died, she inherited all his companies, including Wentworth Tool & Die, which Cliff then restructured as Barnes-Wentworth.
Okay so far.
He eventually sold Wentworth Tool & Die to Bobby and it merged with Ewing Oil in the final season of the old show. This is when Bobby then offered Cliff a partnership at the new Ewing Oil he was launching (after the government seized the "original" Ewing Oil.) This of course did not leave J.R. very happy, as he was not working in oil at the time, but he did eventually return after spending a night trapped in an elevator with Bobby and a crate of fancy wine.
Cliff sold Barnes-Wentworth to Westar at the beginning of Season 12 when he was despondent after his wild-goose chase for Pam led to a meeting with a different actress wearing rubber burn makeup.
Bobby offered Cliff a partnership in the new Ewing Oil after he won approval from the government to use the name again, in part because Cliff had the cash on hand he needed to buy Clayton's refinery. J.R. also came back on board, because he owned the former Ewing Oil assets, but wasn't allowed to become a full partner again until after the night he and Bobby were trapped in the elevator. This led to the usual friction between Cliff and J.R., with Bobby trying to play peacemaker.
Cliff ultimately took his ball and left during Season 13 after J.R.'s P.O.S. oil tanker collided with Westar's during a storm at sea. Cliff then heads up the state investigation into the accident, and is later named head of the state's Oil Regulatory Commission.
[/quote]I'm a bit cloudy on the details (its been a while since I watched the final season), but Leann De La Vega swoops in and buys Ewing Oil out from under J.R. and Cliff and sells it to Michelle (April's sister.) Cliff wound up marrying Michelle in the final season to get control of Ewing Oil and ends the series as the sole owner, much to the chagrin of J.R.[/quote]
Cliff is long gone when LeeAnn De La Vega buys Ewing Oil; Bobby sells it to her because he wants out of the business following April's death, and J.R. is left standing by the wayside because the feds won't let him take over the company on account of past shenanigans. LeeAnn then sells the company to Michelle for a song as a parting "fuck you" to J.R., and Michelle's first act as the new president of Ewing Oil is to fire J.R.
I'm down to the last five episodes, so I assume the rest of your summing up is accurate, but I did want to untangle those other events.
Holy hell, I need to step away from the TV.