No, I don't see any resemblence with the acting between Willie & Carl. Willie was usually high strung and nervous, not silly like Carl was. Probably the only time I saw Willy acting exceptionally silly was when he was teasing Adam with that half eaten chicken leg!
I liked how John Karlen portrayed both characters, each one with a unique style of his own. Carl was a total hoot too!
As for the other actors/actresses, well for me, Josette, Maggie & Rachel were all pretty much the same. From the way the sentences were said, the stance & poise, to the pauses in between sentences, IMHO the only difference I saw between them was the different hairstyles & clothing. Lady Kitty I liked and thought she was played completely different from the other three.
All of Roger Davis' characters acted the same way also. With the exception of Dirk Wilkins, I couldn't tell who was who from time to time.