But that is just your head-canon. We are talking about what the game is presenting us/our characters.
Everything I've used is in game. the druid grove siding with harpers in the past. The Emerald Enclave, The random heros, Balders Gates having guards, the goblins, Raphael, the creche. All of it is mentioned or found when you enter the grove.
You wrote a lot and made some good points
A lot of it is meta information though.
Example 1: How would my character know what Helsin was planning ahead of time? And honestly, if an evil character did have full knowledge of the situation, then it would be best to leave both parties at their throats in a stalemate that leaves my character room to operate and play them against each other.
Example 2: how would a character not from this area know about the current political situation topside in Faerun, let alone the localized situation in BG. If you are a Gith, you aren't even hanging out in this plane of existence very often.
Example 3: And I think this is the crux of both of these posts: How in the world would my character know about Priestess Guts and the opportunities that the goblin army presents?
#1 helsin is good do to certain readables within the grove, also he has invited the refugees to stay, when everyone else in the grove is against it. Also other readables inside the grove tell of the groves past. By talking to the refugees, and druids you learn more of the going on around you. The frequent attacks by monster races, you yourself witnessed goblins attacking the grove.
#2. Again by talking to the refugees you learn about your immedaite surroundings, by talking to the druids you learn of their feelings towards the refugees, and also the current politics of the druids. Which by more talking you learn that more about Halsin. Then by looking at readables you learn yet more about him, again another conversation and you learn more about him. By exploring the camp and talking to certain people you learn of Priestess Guts. Knowing about Heros, and Balder Gate guards is simple Heros are always searching for evil, and alot of history which you learn in Menzobarean deals with Lloths truimphs over these Heros. A city having guards patrolling is just common sense, all cities have guards, they are always on the lookout. Drow raid topside so they learn about the land above them. As for Gith her information is coming from a conversation with La'eazel, also La'eazel is always vocal about how the creche will provide a cure. So again conversations, reading, exploring inside and before the Grove leads to these non meta information.
#3 again it comes from talking to certain people or person within the Grove. As for goblins most everyone knows about/heard about goblin raids, and goblin ambushes etc. Bards sing of deeds down by mighty hero's, maybe a Hero themself once talked to your character. As a drow my character's house even if minor would have goblin slaves, among other slaves. Also again the history taught within the drow schools to the Drow, or even her parents. Then after witnessing the goblin attack, talking, exploring, and reading whats laying about, or things that just happen to fall into your lap.
Your character may find all of this out. If they don't then he/she may, or may not come to the same conclussion. I was just proposing one, of several different conclusions and plots that may come to mind. Maybe they miss one thing only to learn about it in another encounter, maybe they feel that Halsin will never be a threat to them, so they side with him. Without moving past the Grove I've came up with several different options just from what I gathered in that one spot, and talking to my companions. It can further evolve as you get a better sense of everything through more encounters, the one I presented is theoritically sound, and may very well be what your character comes up with. yet as a theory based off information gathered it isn't proven in fact and therefore needs more investigation by my character. Then there is what may or may not happen on the road that may sway her into a different view, or another theory. Also her personal goals may change, therefore opening up different avenues of thought, and alternative theories. Which as of yet are not plans, just theories, based upon information gathering, and knowledge of goblins, and other monster races.
