I'm about 99% on this one but Duchess positioning should have no effect on the damage decrease passive, as nothing needs to trigger it whereas Seeker and Sandlashed have conditions that must be met to trigger theirs. 

Lol, I've been advised the exact opposite.  I have no proof though. 

I've polled a few people who I trust on interpretations. But given the well, ambiguity of how certain interactions can/do work, I'm not shocked that it's polarizing. As I see it: 

Sandlashed and Seeker have conditional passives which have requirements to trigger, essentially working in opposite directions with Seeker needing to be hit and Sandlashed not needing to be hit. Hence placement being a thing.

Whereas Duchess has a permanent passive that doesn't need to check off any requirements in this instance other than are we getting hit with an AoE. 

In theory they're just a system of if/then statements going in order.

Thanks a lot for your explanation.

I also think that in case of Duchess the position should not matter according to her description. However, I do not know how it is coded. 

For instance I never thought that there is special non interaction of Demonlord's passive gathering fury and ally protection. Therefore, I am just wondering, if Duchess passive contains a hidden feature according the game code.

I think we all agree that it should not matter, but my source assures me it does.  I'm not even sure how to test? Maybe in DT floors, 

The  answer to  your  question is  both  Yes  &  No.

I've polled a few people who I trust on interpretations. But given the well, ambiguity of how certain interactions can/do work, I'm not shocked that it's polarizing. As I see it: 

Sandlashed and Seeker have conditional passives which have requirements to trigger, essentially working in opposite directions with Seeker needing to be hit and Sandlashed not needing to be hit. Hence placement being a thing.

Whereas Duchess has a permanent passive that doesn't need to check off any requirements in this instance other than are we getting hit with an AoE. 

In theory they're just a system of if/then statements going in order.

Seeker and Krisk first. Vogoth and Uugo last. Sandlashed after the champs you want protected.

As an ABSOLUTE Duchess abuser, her order in the team makes no difference. Her and Coffin Smasher protect the whole team regardless of positioning.

Thanks a lot for your answer.

I did some testing in DT waves with duchess in middle and identical champs in other positions.  Damage taken was identical for those before and after duchess.