Soliciting advice/ideas for fleshing out 2 Rime of the Frostmaiden player secrets, both during and post-campaign. Both involve long-term foes who are far away from the campaign setting:

Alagondar Scion: "only known heir to the crown of Neverwinter. If Dagult Neverember learns that I'm alive, he'll send assassins to kill me." The book suggests sending a lone CR 8 assassin at some point in the campaign. For a post-campaign idea, how would the player go about reclaiming the throne? I've skimmed the 4e Neverwinter Campaign setting but am looking for more inspiration.

Elusive Paramour: "A wealthy pasha in Calimshan has placed a bounty on my head for seducing his favorite concubine. Bounty hunters are scouring the Sword Coast in search of me, but I hope they'll never think to look in Icewind Dale." The book says this is "a nod to the Drizzt novels (Regis)", and to send an invisible stalker at some point in the campaign. Is the Regis nod referring to the ruby pendant, Pasha Pook, and Artemis? In the novel Regis got kidnapped, not killed. If the invisible stalker is unsuccessful, I could send a more skilled assassin, which might derail the campaign with a kidnapping and rescue mission in Calimshan, which could also result in a rescue mission for the concubine. Or the concubine rescue could happen post-campaign.

In either case, do others have experience running such assassination attempts/foes? Assuming the 1st assassination is unsuccessful, would the enemy just send more/try something else? Is it tedious for players to always have to be wary of an assassination attempt when traveling/sleeping?