Laquatus, Gaea's Blessing.

[Offler]

Lets say i have infinite mana.

I will play Ambassador Laquatus and activate his ability, lets say 50 times to mill 150 cards.

Opponent has Gaea's Blessing, Guile and other cards with same mechanic.

As the stacked abilities of Laquatus resolve Gaea's Blessing enters the grave.

What is the position of its trigerred ability on stack?

If its on top, I would like to activate laquatus 50x times, and then with other shuffler again until the library is completely in grave. At this point i want to activate Tormod's Crypt, Relic of Progenitus or similar grave removal.

As far i know this would remove all opponnents card from the game while the trigerred abilities will not shuffle anything back to library. At the draw step they would lose the game. I was trying to find any problem which would prevent the combo to work, however i found no problem there, just i am unsure - since its the part of finishing move i would not underestimate anything. And also because "you cannot mill my library, i play gaea's cradle". Some people did not understood why i was able to discard them.

[luma]

When Gaea's Blessing, Guile or another similar card is milled, its ability triggers and is put on the top of the stack. You can respond to the ability by activating Laquatus again in response, thus milling his whole library before Gaea's Blessing resolves (and then you can exile the graveyard with Crypt or something).

Just note, that some effects (like on Progenitus) are replacement effects. You can't respond to them, and the card never even hits the graveyard. You can recognize them for "if ~ would be put into a graveyard" instead of "when ~ is put into a graveyard".

[Offler]

And Replacement effects are static abilities, thanks a lot :) I never noticed the difference on progenitus.

What about Leyline of the Void, if I try to mill Progenitus?

Leyline has very similar replacement effect.

[Julian23]

When two or more replacement effects would apply to the same event, the affected player chooses one. If the event affects game objects, the controller of the affected object makes the choice. That effect is applied.