Has anyone found something like the DNA in CK I for modding in your own character?
Yes, every character has a DNA string that can be scripted in and modded. There is a dev diary by
podcat on the subject (see the dev diary archive). The properties that can be modded are found in a file under
interface if I don't remember incorrectly.
Also, why can't the King of Poland swear fealty to the Emperor?
The HRE aren't to keen on letting in a vassal that would be too powerful. This was easily exploited by many betas and devs.