I'm aware of all of this and have been for a long time. My concern is that, depending on the way the skirmishers are organized, the family info sharing mechanic could be either incredibly powerful or completely pointless to the point of making skirmishers near-useless as a coherent defensive force.
Let's imagine a hypothetical situation in which a sizable, organized raiding party of sixteen Nerans backed by a neighboring kingdom is coming to steal goods from a border county. Let's not even take into account the possibility of full-on invasion for now; we'll stick to minor, everyday threats for the purposes of this thought experiment. We'll even give the skirmishers the advantage that one of them was out patrolling the surrounding lands of the county and happened to spot the raiders before they got near the settlement, giving ample time to react.
Depending on how the skirmishers are organized, this could play out in one of two ways:
If the skirmishers are family bound TO THEIR SETTLEMENT: Skirmisher A, bound to a small farming hamlet along with one other skirmisher, spots the raiders crossing the county border and the 10 people in his settlement "family" are alerted, including the one other skirmisher who lives there. The civilians hole up in their homes, and the skirmisher prepares to defend the hamlet along with his one companion. With what little time they have, a courier is dispatched to alert the four skirmishers living in a nearby trading village, who may be able to eventually get word to the county seat, which is on the other side of the county and will take a while to notify of the threat. The four skirmishers from the village arrive just in time to help the hamlet's two skirmishers mount a defense, but brutally outnumbered sixteen to six, they are defeated and the hamlet's entire crop for the year is stolen, along with many of the family's possessions including farming implements, weapons, etc. Word eventually gets to the county seat, but by the time it does, the hamlet is all but destroyed.
If the skirmishers are family bound TO EACH OTHER: Skirmisher A, bound to all of the other skirmishers in the duchy, spots the raiders crossing the county border and all of the skirmishers in the realm are alerted. Those close enough to arrive in time set out in defense of the hamlet. Skirmisher B, back at the hamlet, tells the members of the settlement family to hole up inside their homes while they wait for help to arrive. Soon, every skirmisher in the county and a fair number from the adjacent counties make their way to the hamlet, well in advance of the slow, bulky Neran raiders reaching their target. Now outnumbered and facing a force that is much better adapted to the local environment, the Nerans turn back, losing a few men in the process and gaining nothing from their feeble attempt at a raid. The people of the hamlet thank the skirmishers, who return home satisfied that they've done their part to defend the realm from outsiders who would do them harm.
See the difference here? In the first example, the info sharing mechanic is unreliable at best and nearly useless at worst, in terms of gathering a coherent defensive force. Sure, maybe if there are enough people mixed around outside of their home settlements, word might get around anyway. There might be a merchant from Settlement B in the hamlet at the time, meaning Settlement B would hear of the attack on Settlement A, and maybe someone from Settlement C is visiting his sister in Settlement B and hears the news of the attack, and so on... but this would be slow and unreliable, and it's entirely possible that a threat could arise and nobody outside of the target settlement would find out until it was too late.
Contrast that with the other situation in which all of the sworn defenders of the realm immediately know that a threat has been identified and are able to respond without delay. This is the kind of advantage that would offset the feeble numbers that the skirmishers are working with, and it sounds like maybe, maybe, this is actually how it works. I just want to know for sure whether that's correct or not before I pledge my county to an area of the world that may or may not be realistically defensible.