So don't take it personal if I don't respond to you anymore as you have taken it personal in the past when I don't respond to you. It is simply me respectfully declining to comment any further on your opinions and criticisms.
I wondered how long will you keep your word ...
Cant say im surprised.

And you see that where exactly?
https://www.britannica.com/topic/Occams-razor 
Lets sumarize facts:
Everyone in the Grove are talking about attacks ... Druids even blame Tieflings for that ...
Sazza was captured ...
Minthara do not know where the Grove is (or at least she certainly didnt when Sazza's group went off) ...
Logical conclusion:
There was *some* Goblin attack to the Grove ... that is not even conclusion, that is just repeating first fact.
Sazza was captured in *some* previous attack ... since she is not part of curently attacking group, and we know well that none of them survived AND she is in prison this whole time ... logicaly (i really cant explain it differently) she had to be captured in the past ... was that day? week? month? dont know, dont care, not important anyway.
Minthara do not know where the Grove is ... she ordered Spike to torture adventurer so he tells her Grove location ... either she is sadistical bitch (wich i cant confrim nor deny), or she dont know that location yet ... logical conclusion if she do not know location, no scout ever get back to her to report their findings.
Its all right there, what more do you need?

I mean seriously ... PLEASE give me example of provided information you want from Larian ... bcs i cant imagine anything that would not sound ridiculous.

goblins were wiped out every time they found the Grove during every attack. Not one goblin was able to escape. So the tieflings have fought off the goblins from the top of the wall several times now, and not one goblin was able to get away. Is that what you're saying?
Nope, technicaly its what Larian is saying ...
Again ...
If there was no attack > none in Grove would be talking about attacks (plural).
If Minthara knew the location > she would not praize Sazza, or you, or Spike ... for "finaly giving her that location".
Simple as that, basic logic.
And what makes Sazza so special? If the Grove was attacked by goblins several times in the past few months, why aren't there other captured goblins? If they killed all the others, why keep her alive?
If i should use your own logic against you ... i would ask: Where exactly you see that she is anyhow special, or that someone planned to capture her?
I dunno how much you are interested in REAL history battles ...
But its nothing uncommon that after you search the battlefield, you find some enemies just unconcious, or suffering non-lethal injuries ...
And when a similar situation arises, why not make maximum of it? :P
I could imagine you asking right now "why only Sazza, chances that she would be the only one by all that *unspecified* time are quite thin" ... and you are right, there gets another logical asumption, every prisoner means another mouth to feed (otherwise you could just finish them here and now), another space (cage) to store, and most of all higher chance of escape with every single one you bring ... so, keeping their numbers low isnt so ilogical move.
It is never explained why they chose to capture Sazza and lock her up. Are they hoping to interrogate her? If so, what for?
Geez, this is hard question ... what possible information could alive prisoner have in armed conflict. *thinking*
Oh maybe i find something she possibly could tell them ... LITTERALY ANYTHING!

Few examples:
Location to Underdark entrance, number of Goblins in camp, number of their Leaders, anything about The Absolute, their exact location, their defences, how many others know location of the Grove, why are they even attacking the Grove in the first place, ...
You name it, possibilities are endless and chances you would miss is quite thin.

And why isn't there a guard posted to guard her?
I dunno ... maybe Tieflings didnt think she need one, since they didnt count with stupid PC that will locpick her lock that was from the other, and for Sazza obviously unreachable (since she didnt escape so far), site ...
Or Tieflings are just idiots (quite possible, concidering how easily you can get out of their "prison" right opposite of Sazza's cage).
Your gues are as good as mine.

It is clear that she is supposed to be from the same goblin raiders who chased the adventurers. However, she was not in the battlefield.
I really dont know how to react on this ...
You claim that something "is clear" yet with the very next sentence you contradict that. O_o
I mean, if something takes you exactly "to the next sentence" until it stop being true ... i would say its anything but clear.

Shall i presume it was a typo?
Since if you wanted to say that it is clear that she is NOT supposed to be from the same goblin raider who chased the adventurers (Aradin) ... then yes, i agree for 100%.
So did they catch her sneaking in through the secret tunnels? Did she try to sneak in some other way? How did she find a way in? How did the bug bear find his way in? You know, the one who attacked the pink haired tiefling?
Indeed we do not know.
But i dont think this information is anyhow vital for us. O_o
Would she be anyhow less inprisoned if she came from one way, or another? O_o
My gues is that she was part of another scouting party, that was searching for the Grove and get too close.
Why? No particular reason, no particular proof ... its just the path of no less resistance.

And why is no one concerned that these individuals managed to sneak in? Shouldn't they be looking for how the goblin and the bug bear got into the Grove? Shouldn't they be looking for more?
That sounds like logical reaction ...
And since they dont, i dare to say we can safely presume that she did not sneak in ...
About Bugbear, that is kinda puzzling to be true ...
Not just how Bugbear get to that place ... but how did he get into service of his Hell-master(/mistress?) in first place. O_o
(i would like to believe that he was just placeholder for different model)
In my first playthrough of the game, I remember actually thinking that Sazza had been captured during a previous raid. However, if you free her, she makes it quite clear that she was a part of the most recent attack. So which is it? Was she captured from a recent attack or from a previous attack?
Dunno, i would have to hear or see that sentence ...
But lets say you are right and it was no missunderstanding ... or in other words, lets say that Sazza specificaly say that she was part of the most recent attack (wich i kinda doubt, but its possible im also human and therefore cabaple of making misstake) ... from her perspective it could easily be true.
And im not just talking about the fact that since she was captured she have no idea if another scouting party was send off or not ... therefore her party is the "last one she knows about" ... but also about that detail, that party wich was chasing Aradin and his group could be entirely off the schedule.
Wild Theory:
Lets say if Minthara send scouts every Monday ...
Sazza was capture on Tuesday ...
Aradin was discovered on Friday Night ...
And battle before Grove happened on Saturday in the morning ...
Wich simmilar scenario, Sazza could easily expect that Minthara didnt yet send another party, since she was not in that cage for 7 days yet.
And again, no there is nothing prooving this is exactly the case, that is why its called wild theory.

But simmilar scenario (not this exactly) would explain why Sazza said that she was part of last party, even tho we know that she certainly was not.
The backstory of the phase spider matriarch is one of my favorite stories in the game. I like that I had to find a lot of clues in order to piece together her entire story. I would not have wanted this story spelled out clearly for me in the game because that would have taken away from the mystery. I think that how they developed this side story was well done.
I thought that the toll house was pretty good too. I was able to piece that story together pretty well without too much trouble.
Yup i see that the same.
That is why it baffles me that more important story plot elements are not as clearly given to the player.
That is the thing ...
It seems to me that it is, but for some reasons i dont quite understand you stick there asumptions that i cannot connect with anything ...
Like when you said that Tieflings was attacked on the road by Gnolls (that much is okey, that whiny Bard said exactly that) ... and Halsin rescued them and lead them to the Grove. O_o
I have litteraly zero idea where did you get that from.
- There was no indication (at least as far as i know) that Halsin came to contact with Tieflings anytime sooner than in the Grove.
- If you were right with this asumption, it would not explain Tiefling corpses inside Blighted Willage.
- It would cause quite lot trouble explaining what looters Goblins were talking about.
- It caused kinda problem with Sazza talking about some looters, what seemingly could be Aradin and his group, wich also do not make sence since when they were in Goblin terytory, she was allready in her cage.
But, once i start presuming that you were simply wrong ... and Tieflings traveled after Gnoll attack to the Blighted Willage, from where they were chased by *curently mooving in* Goblins into Emerald Grove ... sudently:
- Corpses are explained.
- Tieflings marked as Looters start make sence.
- Aradin is freed of this acusation.
- Sazza is talking about people who were in Goblin teritory before her capture.
And now it all makes sence to me, just as easily as with Toll house, and Spider Matriarch.