Frump is not a big part, but has a few songs and is very important. Conniving little man who has his job only through nepotism and blackmail. Company Way (reprise) and Been a Long Day (reprise) are the ones I remember right now. In the Matthew Broderick revival in the 90's? Frump was sometimes sung and sometimes spoken. Fun role.
Twimble is a company man, Company Way is simple and not too hard. If your school follows it, then Twimble also comes in the second act as Wally Womper, the CEO of the World Wide Wicket Company. Bit part at the end.
break a leg, I love this show so much this would be one I would want to direct again.