Nice summation of year-long discussion about Light Spriggats on the old forums, im2msart4u. The only really debatable moment is the one about not all demales being Light, but, methinks, it's not too important. In addendum, there is a proposed unit in the Formulated Enemy Ideas thread.
Personally, I agree with all of the prossible bio points up to the Republic era, after that it's less clear: I can see how, with time, they can emerge back into the society and not fear persecution from Shadowling Loyalists, but little is known on the subject matter at the moment.