You can't use AngieApplication::useModel()
or AngieApplication::setForAutoload()
to override built in classes, but to replace them. In order to "override", you would need to fully replace the existing classes and alter the methods that you need.
Approach that you decided to go with is not recommended. I think you should move back a bit and we should start discussing this from the perspective of a problem that you are trying to solve, instead of implementation that you had in mind (I think that you picked the wrong approach, but can't be 100% sure until I hear what exactly are you trying to achieve).