I was somewhat let down with the character connection in Edge of Anarchy, so I've been thinking about a different approach. I think I have one that will be cool:

The characters happen upon a living Zellara being accosted by Red Mantis assassins. As the PCs intervene, one of the assassins lands a death blow and the two assassins escape. Zellara imparts the PCs with information using her dying breaths - "Gaedren Lamm, Old Fishery, save my son Eran". Some detective work on the PCs part can lead them to finding the Old Fishery. Eran remains one of Lamm's Lambs - a nine year old boy. In my campaign, I am planning to make Zellara one of Eodred's past lovers and have Eran be his illegimate son (on consequently heir to the throne of Korvosa). This will make for a very interesting twist in the campaign as Neolandus will have this knowledge. The PCs will not only need to de-throne Ileosa, but also keep the heir alive to take his rightful place upon the throne at the conclusion of the campaign.

I had hoped that the final chapter of the AP would outline the succession to the throne assuming Ileosa were removed, so you might consider that there are already wheels in motion that would contradict with that aspect of your proposed alternatives.

Otherwise it is a good way to link the Red Mantis Assassins to Queen Ileosa further, though depending upon how quickly the party learns that Endris is a potential heir to the throne this has its own potential issues.

What will you do with Eran once he is rescued by the PCs? Why would the Queen be more interested in Sabor than in Eran?

I hope this is a fun alternative for your group.

I was somewhat let down with the character connection in Edge of Anarchy, so I've been thinking about a different approach. I think I have one that will be cool:

The characters happen upon a living Zellara being accosted by Red Mantis assassins. As the PCs intervene, one of the assassins lands a death blow and the two assassins escape. Zellara imparts the PCs with information using her dying breaths - "Gaedren Lamm, Old Fishery, save my son Eran". Some detective work on the PCs part can lead them to finding the Old Fishery. Eran remains one of Lamm's Lambs - a nine year old boy. In my campaign, I am planning to make Zellara one of Eodred's past lovers and have Eran be his illegimate son (on consequently heir to the throne of Korvosa). This will make for a very interesting twist in the campaign as Neolandus will have this knowledge. The PCs will not only need to de-throne Ileosa, but also keep the heir alive to take his rightful place upon the throne at the conclusion of the campaign.

Interesting but if the king has an illegimate son, the curse didn't work, so?

What will you do with Eran once he is rescued by the PCs? Why would the Queen be more interested in Sabor than in Eran?

Ileosa still needs a scapegoat for the King's death, so that explains her continued interest in Sabor. I think my angle on Eran is that the Red Mantis did not get the information from Zellara, so they do not know that the illegitimate heir exists. Ileosa came across Zellara's name in Neolandus' journals - the excerpt just said "she has a secret which could destroy the monarchy." Ileosa had her assassinated to hide this secret, not knowing the secret was an illegitimate heir who still lives. I will probably tie Eran in with the Trinia/Vencarlo angle somehow so he escapes the city with Trinia. Not sure how I'm going to develop to the PCs that Eran is the rightful heir to the throne - probably through Zellara. Just have her be cryptic that he is important somehow and must be kept alive.

Interesting but if the king has an illegimate son, the curse didn't work, so?

If the king is still alive, what about the curse? What about the Queen and her way to rule the city?
I don't thnik that you can use it with the same name of the campaign, but, you can do what you want. It's an interesting point of view.

Curses are meant to be broken (or started anew). The PCs will not know Eran is the heir to the throne right away - I will probably have Zellara reveal this at a later date, with her informing the PCs initially that he is important but not releasing the details of that importance. By the time the PCs do find this out (when they rescue Neolandus in Escape from Old Korvosa), Ileosa has grown powerful and entrenched herself in the ruling seat, so even if the PCs brought forth this information they would not have the might to install Eran on the throne. They must continue along the AP to learn about the Fangs of Kazavon and recover Serithtial to be able to face Ileosa in the final installment. All of this just adds an extra twist to the plotline of the AP.

By the time the PCs do find this out (when they rescue Neolandus in Escape from Old Korvosa), Ileosa has grown powerful and entrenched herself in the ruling seat, so even if the PCs brought forth this information they would not have the might to install Eran on the throne. They must continue along the AP to learn about the Fangs of Kazavon and recover Serithtial to be able to face Ileosa in the final installment. All of this just adds an extra twist to the plotline of the AP.

What may happen also it that the PCs decide that with the legitimate heir to the throne in their care, they have sufficient credibility as freedom fighters and may rally nobles and military officiers to their cause. This could lead to a very different campaign.

We had fun with the Harrow cards drawing the characters together; had sort of a "Keyser Soze" feel to it. "Who is this person who brought us all together, and why?" That two of the characters are Varisians with the Harrowed feat, so that might have something to do with it.

I like that your twist on the opening to the campaign incorporates some cool political elements.

I don't like that it is predicated on the very tired, "a group of exceptionally skilled adventurer-types are in the same area, and happen upon this one scene, and..." method of bringing PCs together. Paizo took a different approach to kicking things off. That was the hook that got me interested in using the campaign as our Pathfinder RPG playtest.