This seems like contradiction ...
On other site you say its not a sectet ... on other hand you say that player need to pick all litthe hints and take them together so he know this option is there.
That is definition of secret for me.

It's not a secret to the player because it's pretty easy to run into the chance to join it. If you follow Wyll's plan to take out the goblin leaders-which is necessary to complete his companion quest-then you'll walk into Minthara and she'll present to you the option to join in on the attack at the grove and you'll have the option to join it. It's not something that the player has to work to find. Maybe I just did everything right the first time and it's actually far harder to run into that situation, if that's the case then I can admit that I'm wrong. But based on my experience it seems like playing the game normally has you running into the option to join them without particular work on the players part.
Ofcourse you get the most if you create ridiculously thrusting character, who will tells about his little problem to anyone he can.

No arguments there, you're just plane right. :P
You mean the information about how was your tadpole alterned?
Yup there is one ...
Thanks for letting me know. I have not managed to get to the Underdark at all, the puzzle was bugged in my first playthrough and I haven't been able to get through another despite starting a couple.
Volo is special case ...
You need to save him, offer him place in your camp and then tell him about the tadpole.
He seem very comfident about his skills and knowledge, but never offers any actual proof ... so its just the same about all others, you either thrust him ... or not.

He offers a cure? I thought Volo was just some bard. Clearly I need to interact with him next time because I want to know what that's about.
As i explained abowe, its just matter of point of view ...
Personaly i dont find druids much thrustworthy:
- Their acting leader is openly preparing to little genocide ...
- Healer you are offered tryes to poison you first ...
- And their actual leader refuse to even hear about your problem, before he do his own work ... and he keep refusing to hear about your problem, even after you do that work for him (true, its too late to change sides at this point, but you get me ... right?)
You make a lot of good points here, I can't and won't argue with them.
That is the sweetest part about this group ... you dont need to thrust them at all.

When I say trust here, I mean trust that they have the capacity, the actual ability to help you at all. Not that they will help you, but that they have anything to actually offer you.
You say that you presume that the Absolute path should be "equally viatble story branch" ... yet you also admits that its not acting like it ... isnt that allone kinda proof that your original presumation was not quite right?

It's not a contradiction because I'm saying that it looks like it should be an equally viable branch, based on knowledge of the cRPG genre and my experiences of this specific game, as well as metatextual knowledge based on how the developers have talked about the path. Therefore when I say that it's not acting like one, that's me saying that it's failing to be the equally viable branch it seems like it's being presented as. Like how if you show me a car and I say that it's not driving because it's missing parts, I'm not saying that it's not a car, I'm saying that it's a broken car. Again, if I just am wrong about how easy it is to find a chance to join the Absolute and how obvious it's made to the player, I'll accept reasoning to the contrary.
However I will reccomend Tyranny, it's a great game with a magic system I'm still in love with to this day.
That would mean there is some character that knows everything about the Absolute, yet its not part of her cult ... also knows everything about mind flayers, yet its not part of their hive mind ... also know everything about your particular tadpole, including the fact that you have tadpole, yet either its not tadpoled himself, or for some reason decided to NOT take advantage of all informations he have ...
The only person i can imagine that would check all theese points, yet feels natural in the story, is simply yourself. O_o
Wich, when i think about it ... seem actualy doable!
How about this scenario:
1) When you talk to Minthara, she tells you that Goblins will attack next day by dawn
2) Your quest log will update to tells you that you need to long rest, before progress futher
3) When you lay down to sleep, you get introspective conversation with yourself, sumarizing your situation ... something like:
"Before you go to sleep, you recap your so far knowledge ...
On one hand you have Tiefling refugees, maybe not all of them exactly innocent, but certainly needing your help.
You remember druids talking about Halsin, he might be able to help you, if he still lives (concidering you didnt save him yet).
On the other hand you have cult of the Absolute ... they certainly have some connection to mind flayer tadpoles ... but are they masters, or slaves?
You realize that you need to choose side in upcoming conflict, and you need to choose soon."
Then scene goes as it does now ...
You go to the gate, talk to Zevlor, blow the horn ... and then decide either to betray Zevlor, or Minthara.
What you suggest wouldn't strictly be a bad approach, but I don't think that what I suggested requires someone who knows all the things you claim they know. It's the same way people keep saying Halsin can help even though they don't know that for an objective fact, as you've said before. It would just need to be someone who knows they've got a tadpole and thinks that the cult looks good. Frankly, I think that even just having a member of your party being in favour of the cult would achieve more or less the same result. Someone making a case that joining the cult is a good idea. They don't need to be anymore trustworthy than any of the people pointing you to Halsin.
On anothr note, I just want to make sure you know that while I am arguing against your points, I don't intend there to be any contention. I think your points are all valid and while I disagree, I do understand where you're coming from.