I think a lot of the confusion here is down to terminology:-

I thought "Travis" picking was when you used the heel of the right hand to damp the bass strings of a cross pick style -a good example is Doc Watson playing "Deep River Blues"

Deep River Blues

You can see the heel damp in the second half of the clip.

I thought "Clawhammer" was a banjo style rather like frailing but with more used of melody notes and drop thumbing, but even the tutor books seem the vary a bit on this.