DRWEL, I will tell you who I had in mind in 1986:
The Queen: Maggie Smith, Eileen Brennan, Carol Burnett (Paula Lawrence)
The King: Ellis Rabb, Phillip Bosco (Robert Fitch)
The Prince: Jimmy Brennan (Reed Jones)
The Princess: Rebecca Luker (Rebecca Luker)
Mowgli: Greg Louganis (Davis Gaines)
Eva Standing: Kaye Ballard (Carole Shelley)
Karen O'Kane: Pamela Sousa, Karen Ziemba (Alyson Reed)
Eric Dare: Ron Raines, Howard McGillan (Patrick Quinn)
Those in parentheses did the roles in March 1986.
For 1998, Carnegie Hall, Herb Ross ignored every suggestion I made, except one, which was this cast:
The Queen: Carole Shelley, Carole Burnett, Maggie Smith (Bea Arthur)
The King: Simon Jones, Phillip Bosco (Michael Jeeter)
The Prince: David Elder, Damien Woetzel (Damian Woetzel)
The Princess: Rebecca Luker, Patty Cohenour (Alice Ripley)
Mowgli: Brendan Fraser (Bob Paris)
Eva Standing: Kaye Ballard (Tyne Daly)
Karen O'Kane: Karen Ziemba, Kristin Chenoweth (Sandy Duncan)
Eric Dare: Howard McGillin, Victor Garber (Stephen Spinella)
Those in parentheses again did the Carnegie Hall event. After having to rescore the Beguine for Sandy and Swimming for Bea, I think Tyne was a real surprise, but poor Bob Paris and Stephen Spinella were totally miscast.