
omg for some reason i completely forgot about how the succession skipped this woman bc of her gender (i thought there was an older brother that she did away with for some reason) but if she was the first in line by order of birth then she was denied her inheritance but somehow avery can get access to that with no legal trouble???? wtf

No no. Even if Avery is a woman, she is still the direct heir because she is the ONLY daughter of the SON (the original heir).
That's why the Duke's daughter tried to kill her. Because, as long as the Duke's son aka Avery's father has an offspring (girl or boy), they will be the direct heir, the first in line.

so I went back and did some reading and saw that Avery's aunt was the second child and feeling she was more capable of being the heir to the dukedom she killed her older brother. But then the duke made Avery's father(her younger brother) the heir because Avery's aunt was a woman. I can't remember what chapter but she mentions how she was cheated out of being the heir because she was a woman. I don't understand the succession rules of Avery being the rightful heir because she is the daughter of the next in line. If Avery's aunt could not be the heir because she was a woman than how can Avery be the heir?

Yes even doe she a women she can still take the title I think as long has she married she not a half breed thing her dad married as long as he married and the other women don't matter what Noble or commoner she still counts as the hire to Duke the the only way the aunt and her kids can get it is when something happens to her which nothing bad or horrible to her
it's still like what to me how he is willing to make Avery the heir of the dukedom when his eldest born child wasn't allowed to be the heir because she was female so why did the rules change now?? not to mention her mom was a commoner. like if we go by the stupid original rules the baron is the most valid heir. His parents were both nobles, he was raised as the heir, and his mother was the first born. Like it would be no so surprise all the people would be against her. I just don't understand the logic at all. I guess he's deciding to disregard the rules because that's what caused the mess??