Jane this is a really interesting question you've asked here. I saw it yesterday and was hoping that someone else would jump in so I could see what they said too! But I'll take a run at this...
I think some of the LS activities have some of the principles "baked in", as they say. For example, TRIZ and Ecocycle both have elements of "inviting creative destruction to enable innovation." They ask, "What can we stop doing?" before they can make space to ask, "What can we start?"
From my group process facilitation work with non-profit and other groups I have seen both sides of this coin. First, groups that seem to not want to come up with new ideas or projects because they have so much on their plate. They can't be innovative, they don't have time in their day to add on something else. Second, groups that - when presented with the opportunity to move through a Liberating Structure - are absolutely gleeful thinking about and talking about what projects they can creatively destroy, so that they can "birth" new initiatives. In the first situation I didn't use LS. In the second I did. This principle works!
But you said you think it's possible to facilitate LS without employing the principles fully. I think sometimes you're right. But that's not the goal, is it? We can be more than that. I think the goal is to bring the principles into the mindset that we carry to our work as facilitators, not just to let them rest interwoven in some of the invitations and instructions of the structures. It has to be both.
Are all of the principles in all of the structures' purpose and instructions? I'm not sure. Keith and Henri and others (Nancy?) might know for sure. But in the approach that we bring as facilitators, it is ideal to bring them all.
Thoughts from others?