Hi, Reuben
Well, Braider is a model plug-in and generally it’s not responsible for any render aspect. As Brian said, it is just a method to generate source lines/curves. So, we can answer for “how particles react to GI”.
They don’t react at all. A ray cannot hit a particle cause it’s a pseudo-geometry has no square. Thus particles cannot cast RT/GI shadows. EI automatically removes particles from GI calculation.
Note also that other possible ways instead of SuperLines (like a creation of real or virtual geometry), would formally work with GI and/or radiosity but unacceptable in practice - illumination calculation is very and very slow for such models. This kind of geometry requires a special technique known as “deep shadows”. But it’s another story.
There are no problems to deform Braider’s output, here lines work absolute same as a polygon model. Some problems appear if the plug-in input (child group) is deformed, in this case you need to use UV space to stabilize. See “spaghetti” animation Uwe posted.
Yes, even it’s a modest feature. Reactive can be used as a clip map to make holes or/and as an amplifier for output chain of segments.