In the previous version, the player and start slave would basically never display pureblood(100%) genes but would always be forced to be pureblood when the game was started, so re-rolling the displayed genes never mattered. The code for assigning genes to unique characters was cleaned up so that the displayed genes are always what you will receive when the game starts. It was also reported by a player that it didn't make sense for halfkins to be purebloods, so halfkins were added as exceptions to the pureblood rule unless Furry was disabled in the Options menu, in which case halfkin would take the place of beastkin in terms of genetics. The 69% animal and 31% human was hard coded for halfkin starting characters when Furry is enabled.
Unique characters will have random genes if you do not have Ralph's Tweaks enabled. (Edit: apparently this was changed and unique characters no longer get random genes) Previous versions did not support Constants mod for changing settings like Ralph's Tweaks so the files had to be manually edited every time. Though if you use Constants mod you will need to restart the game for Ralph's Tweaks to go into effect.
I don't exactly understand your problem related to getting a non-demon child. In the previous version, the race chosen for a child had an un-intended bias. It is intended that the child's race will be a random selection of one of the highest percentages if there is more than one. In the case 25/25/25/25, each race will have 1 in 4 chance to be selected. If you have a reason for wanting a different result, then you will need to clarify why and what you would prefer.
Fetishes were expanded to include several vanilla traits such as "Submissive". Vanilla systems for acquiring those traits such as the start slave's quest line and the sex interact have not been corrected, thus those traits will still be added and then later removed. Currently it is not possible to acquire and keep those traits outside of the daily fetish opinion updates.
