I thought about mentioning Jennifer Laura Thompson, but (disregarding billing) I think that role belongs in leading or at least a good argument can be made that the role belongs there. Fabulous though Nancy Opel was as Penelope Pennywise, that character does not.
I agree about Hunter Foster as that character really is the leading male role, and Hunter Foster was terrific in it. Cladwell is really more a supporting role.
And since we've been talking Ken Jennings, I think he deserved a featured nomination that season.
The Starmites season was certainly among the most desperate of all desperation seasons for the Tonys in terms of musicals. I think we can add that normally neither Robert La Fosse nor Charlotte D'Amboise would have been in leading.