I've actually thought about this, which may be the gayest thing I've ever done.
Frances Conroy as Jessica. Six Feet Under showed her styled like a schoolmarm AND later on as a more relaxed, contemporary woman. As with the original series, she's a childless widow, who starts writing after the unexpected death of her husband, although instead of an illness, he died in a car accident...or did he. The overarching story involves, as Jessica's first book climbs the best-seller list, and she gains notoriety for being able to solve murders, she starts getting clues from someone claiming to be Frank's killer.
JK Simmons as Seth. Like the original series, he's a widower, unlike the original series, he and Jessica have a sexual relationship, which is an open secret around Cabot Cove. He would probably marry her, but as much as she cares for him, her real love is her new career. He is EXTREMELY skeptical of the clues from Frank's alleged killer, but supports her anyway, even though he makes his displeasure known.
Avery Brooks as Amos. Amos has a very antagonistic relationship with Jessica at first, wanting her to stay out of what he considers police business. He slowly begins to trust her insights when she helps clear one of his deputies who was involved in a shooting, but still considers her a bit of a nuisance. The big breakthrough in their relationship comes when he has a tricky case and he has to come to her for her help, which finally begins a friendship between to two of them.
Phillip P Keene as Grady. This time around he is openly gay. He is an unwavering supporter of his Aunt Jess, and is even willing to put himself into harm's way to help her, even if, like the first Grady, he's a little clumsy about it. Grady is married; his husband David (Kirk Acevedo) works for Jessica's publisher. He was the one who helped her her first book on store shelves. He loves Aunt Jess as much as Grady, but is more reluctant in taking on risk, but does so, more to watch out for Grady. Whenever it's necessary for Jessica to come to New York, she stays with them instead of a hotel.
As with the original series, after a few years, Jessica will start dividing her time between her life in Cabot Cove, and a new job teaching creative writing in New York.