There are 2 additions, that would make it even better:
1) Set Experience bonus when creating an Heir and possibly add the Special abilities gained by an Heir.
This could be done as a seperate Character creation "Heir Creation", so it dosen't polute the already great Character creator.
2) Open the option to add Traits, not only exchange them.
Example: You can learn Shadow Lore from Saruman. In addition to the traits you alteady possess. Many other ways to gain additional permanent traits... Small, Elf Friend,.. And many more ways to gain Temporary traits.
So, an optimal solution could be to have two extra options: Add Permanent Trait, and Add Trmporary Trait.
Just my 2 cents

Thank you so much for this tool