...which you amazingly compiled in here:
I downloaded that table time ago, before registering in here, and had some fun with it estimating magi in Stonehenge and Loch Leglean for mi Saga.
Hopshackle also did a pretty good simulation of the Order some years ago, here:
Anyway always remember that the Order Population is around 1240, which is pretty much the size of my home village, and I think know everyone there at least by their face. Each tribunal have an average of around 85 magi who will surely know each other pretty well (things like specialties, sigils, houses, companions, grogs, items, preferred spells). With their high life expectancy the death of a magi is big news (specially if he's not very old or if it was noticeable) probably known pretty fast in his Tribunal and soon in the rest of the Order. Think that even if magi can be pretty secretive they have grogs who met other magi's grogs and gossip around them and spread news around; if you wonder about another magus wereabouts one pretty good option is turning and asking your shield grog about him... the second effortless one is asking your local Redcap. And the third, going to the nearest village to his covenant and asking there. Peasants have boring lifes and you can expect them to know a lot of stuff about the weird old dudes living in that enchanted tower right over there.
There surely are lonewolfs out there but being odd and strange they are probably the focus of more gossip and scrutiny than usual by both magi and mundanes.
This is something often overlooked, but in my Saga I like to make the magi notice that they are part of a small privilegded and closed society, powerful but fragile. We don't have encounters with a random Flambeau magus in the deep of the forest: we find a Flambeau and magi can guess he must be that Provencal's dude the big mouthed Merinita from the neighbour covenant mentioned a couple a months ago, saying that he wrote a letter to a friend of hers talking about paying a visit looking looking for some kind of item his parens lost here during his young years, which was some kind of staff or maybe a sword, because his parens was one of these odd Flambeau fond of cutting through beasts instead of just roasting them.