Hey Hugh - I'm one of the folks working on Loomio too.
In some respects, defining "inclusive" is the hardest question in the world. At Occupy we tried to say "we include everyone". It was a traumatic lesson to learn that is actually an impossible aim: when you include anyone, you include people who's behaviour excludes others.
So if you can't include everyone, how do you draw the boundary?
At Occupy the impossibility of that question proved fatal: almost all of the camps that were lucky enough to avoid the violent state suppression of jackbooted thugs eventually succumbed to that paradox.
I believe we can get closer to a solution if we reframe the question though. Instead of saying "let's include everyone", what happens if we say "let's include everyone that is affected by this decision"?
You can add more nuance to that principle and agree that a person's influence over a decision is in proportion to the degree to which it affects them.
If you can agree a set of interaction protocols that are a prerequisite to participation, and some high-level nonspecific aims, then you can actually start making progress.
Once you have that unifying banner agreed, you can keep decisions action-focussed. Personally, collective decision-making is infinitely more appealing to me when it is used to plan action, rather than trying to agree abstract theory!