Yes, he was the creator as far as I know, apparently in 1979 (ah, the year I saw Led Zeppelin!
).
You mean the posture starting at 1:28, Swing the Rainbow ? Good observation, I never made the potential connection to Lion Holds Ball (and here I curve the torso 'too much' with respect to the bagua posture) but I guess you're right.
The move I really like in this set which seems very bagua-ish to me is Rhinoceros Looks at the Moon, starting at 5:10. I do the first few swings in the orthodox way (in terms of the 18 Movements), putting the weight into the leg/foot on the side toward which you turn. This is better for beginners because it stabilizes the knee of the weighted leg - in this move there's a risk of the torsion/spiral in the spine (good) propagating down into the knee joint (not good). Then after a moment I switch to the variant that I prefer and which is also more bagua-ish, putting the weight into the leg/foot on the other side. This frees up the lower back more and enables the torsion to move more into the lumbar vertebrae, but you have to make sure that the load-bearing knee remains in alignment.
Lift the Moon from the Sea (7:08) is also fairly untypical of tai chi movements and might be more bagua-related, but I don't want to labour the point too far...