Accurate AI Ptolemaic Faction Heir?

Because Ptolemy Soter is included as the first faction leader in the family tree (he is killed by a script before the first turn), his son Philadelphus becomes the faction leader. But, because Philadelphus son Euergetes is only 13, the AI selects a Thracian as the faction heir. The result is that, if Philadelphus is killed before the Thracian dies, the rulers of the Ptolemaic Kingdom aren't the descendants of Ptolemy, but of this Thracian guy (whose name escapes me).
The family tree for the Ptolemaics also includes Philadelphus' older brother Meleagre, but Meleagre gained the crown of Makedon, not Egypt.

Basically, I'm trying to direct the lineage through Philadelphus so that when the AI controls the Ptolemaic Kingdom the rulers remain, for the most part, Ptolemaic.

Thanks

Uh, you do know that you can change your faction heir, right? So even if the Thracian is the heir at the start, once Euergetes is 16, you can name him as heir.

Think of it as a stewardship; in lack of correct descendant, someone else takes over the throne, while waiting for a true heir to come of age.

Thank you for your response, but again, as I said, I'm concerned about the Ptolemies when controlled by the AI.

I think the only real way to change this would be to have Eurgetes older at game start i.e. 16 after one turn....but even then, I don't see how you could "force" the Ptolemaics to follow a certain lineage, as there is inevitably going to be a situation in game where there are no suitable Ptolemaic heirs, so some son-in-law will gain the crown. In real life, I think he would have took the name Ptolemaios.

One question I have is...are we even 100% sure that the direct descendants of Ptolemy ruled over Egypt for 300 years? Surely, a son-in-law must have snuck in there somewhere and renamed himself Ptolemaios. Of course, I don't know all of Ptolemaic history, so I might be wrong.

If it was ruled by direct descendants, wouldn't that make the Ptolemies one of the longest lasting dynasties in history?

Just curious.

Off the top of my head, the House of Savoy existed as a "Dynasty" for nearly 900 years... I don't know enough to say whether it was always through the male-line. Most dynasties (nearly all) followed Agnatic primogenture in which the first born son inherited the possessions of the father (younger brothers of the father inherited only if the father had no male heirs). In England they followed Agnatic-Cognatic primogeniture in which a female could ascend if no male heirs existed.

If you are interested in primogeniture, you should read into Salic Law. Although merely a European creation, most kingdoms of the world, regardless of location or culture, followed a similar system. Its just part of the worldwide conspiracy against second-borns.

...
As for the game, the heir is determined by influence. Thus, I've solved the problem by increasing the influence of Meleagros Ptolemy while decreasing the influence of Leontikes Thraikkos.

What I'd suggest is to have a faction heir who is older than Philadelphus, so that Euergetes has a chance of becoming the heir before Philadelphus dies of old age. But even then it's purely random weather Euergetes has enough influence to become the heir. Anyway it's better to have a Ptolemy in power at least for the first decades.

I think influence only impacts who is automatically selected as faction heir by the AI. It also had an impact on Senate offices in vanilla, but those are gone now. So, I suggest (and I'm almost certain that the EB team has probably already done this for their internal builds), that there be two more traits:

First Born Son, and Son of the Pharoah/ Basileus, King, whatever it is for the faction.

The first born son trait is influence +3 and the Son of (Leader) is influence +2. That way, by merely being born, they have a greater chance of being automatically selected by the AI.