nice submission, that one - though I have to admit, that I have not read it all. I skimmed through the other comments also (especially Art's and Mina's and thought maybe the Aeruillin question could be solved this way (Aeruillin is not developed right now and a lot is undeveloped anyway, so it is difficult to place something there):
A question first: Who writes this report for the compendium? You, Lionhorse - who are you? Are you from Santharia (I don't know your RP char)
If you are writing from a Santharian point of view (if you are living here), then show us, where they are in Santharia. How far spread are they? (I would recommend to have them in the major cities only)
As Mina said - don‘t spread them too far. They may come from Aeruillin, but keep them - or what we know of them, in Santharia. Even if they are in Nybelmar - don‘t mention it. As Art said, they could be linked to Nehtor, have developed as special branch of his healer. If you don‘t like this, see further down.
I think they would have some dependencies, as Art suggested. An organisation of that size has to have some, kind of guild houses, where the individual pharmaceists can take refuge if they travel, where their superiors sit (they have a guild structure after all). You can e.g. have their biggest in Strata (the first place they travelled to, when coming from Aeruillin). Have at least one in the great cities - New Santhala , Milkengrad, perhaps all the province capitals.
You have a lot of stuff in your submission, a Santharian citizen cannot know. But maybe there is a book/ books, where all those information is contained, books which are in the library of one of the depencies, books which the writer of this article was allowed to read. Or parts of them. So you can omit a few things or make them more vague.
A question: did you intent to let them all be educated in Aeruillin, and send out to do there work all over Aeruillin and Santharia? Or did they come from there, settle here and are now educated in Santharia, so that Santharian kids are able to get pharmaceits also? So that only their origin lay in Aeruillin? This way they could be fairly detached by now, after some of the wars and now they are a Santharian ,institution‘?
History is still missing, so we don‘t yet know, how long they practise. I‘m curious to what you are up in this respect.
One last question: Your pharmaceists are healers also? That‘s a bit misleading, for pharmacists nowadays research and prepare medicines, know how to use them. But they are no healers. Maybe you could not call them healers (who can mend a broken bone also), but only pharmaceists or a bit more Santharian (pharma.. Sounds so modern), maybe
Pharmoceists - farmosceists - farmosts .. Don‘t have good ideas today
Herbalists?
To not have just another ,healer‘ I would suggest to make them proficient only with healing through the application of herbs, tinctures etc, but that the people have to go to somebody else, it they have a broken limb or majors wounds. (e.g. after a battle).
Enough for today, I‘m not here anyway

Hope it helps.