Yep, hardcoding the lords in this quest is the simple way and would probably work most of the time, as it´s early game when this quest would fire.
But is it early enough? Things can happen.. This depends on so many thing.
Vlandia must exist, King Derthert must be alive[He usually is the first ruler to die of age in my games] and be the ruler of Vlandia[I know, dethoning a king is not a thing but I hope it will be!], Vartin dey Jelind and his heir Beritor must both be alive and hold Hongard Castle[I don't think AI retract holdings is a thing yet but it was a thing in Warband will centainly be in Bannerlord too at some point. And now any vassal can demand it for 400 influence]. And thats not even touching immersion. Fun to find Vartin RNG:ed as Derthert´s best friend? These things can be considered in a wellmade dynamic quest.
Your image of a Honourable warriors seems to be quite west-europe Christian
But even IRL, most/all cultures had their own "knights", loyal to honour and their set of virtues - which can variate from your set above though
In a low-fantasy setting, the cultural localisation can vary, and also ruler text can very slightly based on his personality but quest could be exactly the same
The most cruel vassal lord with an heir is picked dynamically - should not be a hard thing.
So, I´m not proposing variations of the quest. I propose 1 dynamic quest
Not only for ability to pick your faction to befriend but even more to hold the integrity of the quest-code