I actually love the idea presented in that one post.
Hereditary wise, Vayne is a Demacian Noble. She's technically in line for the Throne if the lightshield line dies. Swain is Currently the first in line to become the next Noxian Ruler, and Leblanc's Order basically Controlled Noxus before the High Command and The coup attempt from Raschallion, the one that sent Annie's Parent's order into self-exile. All this talk about Hidden orders, and Nobody seems to remember these guys have a colony south of the great border, the place that Amumu basically got into the league just because he survived down there.
Also, remember the Withering Curse? The one which only super powerful and super skilled mages could create? What does Kaliyme sound like to you? She seems to be overlooking alot of Black Rose stuff, on Swain's part at least. Remember, Kaliyme is Basically the High Councillor AFTER Ashram just Vanished, and Kayle, the subject of the withering Curse, was searching for information on it.
Also, one more possible connection. Remember what Veigar is apparently doing in Bandle city? Stealing Random ****? Remember what he is, one of the single most powerful mages on Runeterra, if not THE most powerful mage on Runeterra, and remember his objective.
End all Conflict.
Even Teemo said it in the Balloon heist thing, to paraphrase - Don't suspect it's nothing just by what it looks like.
And all of these stories are the super recent ones.