I believe he did do some clawhammer style here and there, and he does show you some of the basics of clawhammer in his book. read more
According to the Happy Traum video "Five-String Banjo for Beginners" Pete Seeger popularized a traditional style of banjo playing and some people called it "Pete Seeger style" but Mr. Seeger never did and called it "basic strum" or "up-picking" style. read more
The clawhammer banjo technique works quite well on a ukulele in the standard GCEA tuning, especially playing in the key of C or the key of G. Since, like the 5-string banjo, there is a string that is higher pitched on the opposite side, the same technique results in the same sound. read more