In episode 6 of Durarara!!×2 Shou, we see Mairu speaking lines that are attributed in chat to "Kyou" (狂) around 18:14. Later on, around 18:44, we hear Mairu's voice actor (Kitamura Eri) speaking lines that are attributed in chat to "San" (参), followed shortly by Kururi's voice actor (Kanemoto Hisako) speaking lines that are attributed to "Kyou".
Then there's the fact that Kururi is taciturn in person but "Kyou" is super-talkative in chat, while Mairu is a chatterbox in person and "San" just occasionally posts one-line replies in chat.
Another thing (which I might be making too much out of) - in episode 2 of Ten, Mika mentions that "San and Kyou are Mairu and Kururi", without specifying which one is which.
And, to be clear, the character used for "Kyou" can also be pronounced "Kuru" (as in 狂う), while the character used for "San" can be pronounced "Mai" (as in 参る) - the chat handles are clearly derived from their names.
I don't see how to reconcile all these details without concluding that both Kururi and Mairu use both "Kyou" and "San" as chat handles at various times. This seems like exactly the sort of trollish thing they would do (runs in the family, I imagine). Am I right in thinking so? Or have I misinterpreted something?