So is it like a multiverse with multiple universes existing and in the different ones, different things happening and that's why sometimes Erin will show up in this or Education? And is there fiction that is shared across the multiverse, for example, in one of the other comics, someone dressed up as Felicity. Or am I thinking too much into this? Anyways, this is all to say, I hope Sintra also shows up in other titles
The degree to which MCC titles take place in the same universe is somewhat fluid. SJI and Beyond Rubies have been established as being in the same universe (DaphneVerse-1), so both characters and plot lines interact. An Education and Expanded Universe likely take place in the same universe (DaphneVerse-2), but a different one from SJI and Beyond Rubies, so characters may appear in both universes but plot lines are not necessarily the same (for example, the DaphneVerse-2 Erin may have moved to New York and never gone to Wilmot).
I won't claim this has been carefully mapped out yet. :-)