I would vote for Byron Scott as the new coach.
He has ties to Sacramento, being an assistant under Adelman. He has had success in New Jersey and New Orleans. It was a no win situation in Cleveland after LeBron left.
He has the championship rings from the Lakers playing years to get the players attention and respect. He is from California and should be eager to put the Cleveland fiasco behind him. Could be an Adelman type coach for the Kings.
As for the GM, at this point, with only a month from the draft, it may be best to give Petrie a one year contract and give him a real owner with real money and see what he can do. Petrie was actually very good when he had money to spend on players.
His drafts have been pretty good, except the last two. But to be fair, Jimmer was a Maloof pick. TRob was a total wiff, but he was rated top 3 by most draft gurus.
It seems late in the game to change GM's, unless you pick someone off another teams GM team. Otherwise, hire a new coach and give Petrie a chance and a real checkbook, and see what he can do.