Other than a horse that is 1/2 or partial Thoroughbred & Quarter Horse, I don't think the AQHA allows 1/2 breed horses to be registered.
And like the others stated, unless you plan on doing AQHA shows with your horse (provided she could be registered), there is no real benefit to registering her with AQHA.
I have no clue about the Kiger registry, however, there are some avid Kiger fans, so registering her with that registry might add a few $$ to her worth, if you can verify her parentage and the Kiger input is well/known or has some worth in the Kiger sphere.
And like the others stated, unless you plan on doing AQHA shows with your horse (provided she could be registered), there is no real benefit to registering her with AQHA.
I have no clue about the Kiger registry, however, there are some avid Kiger fans, so registering her with that registry might add a few $$ to her worth, if you can verify her parentage and the Kiger input is well/known or has some worth in the Kiger sphere.