Pesukim are not sufficient. They are only the beginning.
Look at Seforno
(16-17) ?????? ??”? ??? ????? ??? ?? ???? ??
?? ???? ???? ?? ?? ?????? ?? ??? ?? ?????? ?????. ?? ????? ?????? ?? ??? ????? ???? ?? ?? ???? ?? ??? ?? ???? ?? ???? ???? ??? ????? ?? ???? ?????? ????? ?”? (?”? ??? ?? ??????) ?? ?? ??? ???? ????? ???? ???? ??? ???? ???? ???? ????? ????? ?????? ????? ???? ???? ?????? ???? ???? ?? ?????:
Meaning if the motivation is like/dislike, love/hate then one cannot alter the order. But if it because the son is a Rasha, an evil doer, then it is permissible.
If you look at the Vilna Gaon on the possuk he says it is talking about 2 children from diff wives each one a bechor born at the same time……… not the case in most homes
Thirdly, the possuk speaks of exchanging bechor privileges, not about disinheiritng. It is a din in bechor, not simply rights of Yerusha. I had written previously that one can put into a trust with conditions… that is not quite taking from ne and giving to another and is certainly not challenging the din of Bechor.
Finally, it can all be gifts while one is alive and need not enter the laws of yerusha if one want to set it up that way.
Theres more, but that should address the issue for now. No?