Had to look Jesse up since I've never watched Grey's Anatomy. A very good choice for Jeff. I like your idea of an African/American family as the Colby's. If we're going for a re-boot why not totally re-jig the characters ethnicity. Unlike others I'm prepared to give Dynasty 2.0 a chance by watching with a fresh approach. What would be the point of this whole exercise if the producers copy the original...word for word, same story arc's.
What I also like about having the Colby family as African/American is Diahann Carroll could make a special appearance...not as Dominique Deveraux of course...but as matriarch of the Colby family. Throw in Dame Joan Collins playing Alexis Morell Carrington Dexter Rowan's mother, and we're on a winner.
Maybe not African American, maybe from South Africa - bit British, bit African. The Colby boys meet Blake at boarding school out east. They could strike oil together in Africa and end up in Denver together looking for what oil is left after all the great oil properties were snagged up - only to fight and split up.
The Colby's could stay South Africa with Jason in London running CP - modeled after British Petroleum / BP (C for Colby or Commonwealth). Cecil could run ColbyCo based on Koch Industries in Denver. Global offices, apartments, homes.
DenverCarrington based on Haliburton would be in Denver like the Bushes going to Texas to strike oil. Also a background story of politics, maybe secretary of energy and ambassador to Vietnam.
Steven's company could use advanced fracking technology to get at oil no one could ever get at before - all those once dried up properties.
They'll do deals in Asia and the Middle East - more diversity.
We could see more of Krystal's Hispanic family (Argentina with lots of dislike of the British). The British, the South Africans, and the Argentinas all into polo. Lots of fun interacting around the world.
Blake's sister would be half Asian from Singapore - another British polo playing influence and more diversity.
If done right it won't feel forced but exciting.