[Illyahr]

We really can't do much with Favored Enemy as it's buried too deeply in the code for us to manipulate. It would be too clunky to make a separate Human race for each as, according to the Rokugan Campaign Setting book, each clan also has three or four families that each have a favored class and class skill so I would have to make 30 new human races.

Akutsukai and akutenshi don't work properly as written as the only similar thing is the ghost template and that doesn't work either. If you can get it to work, let us know.

As for variant classes, just select it from optional rules when customizing which books you are using. Making a variant is cleaner than making an entirely new class.