The ears and tail are only optimized for G1 charaxcters. The best way to do ears is to create a custom hair asset for your character and replace the hair it currently has.
Of course if you want to be able to animate the ears, you are better of creating what i call a 'rigged prop', (im sure theres a better name for it out there)
basically just rig up up ears using the prop composer, making all the segments the way you want them and linking them in the proper parenting structure.
You can then attach the props to the body part. But you may be limited by the angles unless you get creative or maybe make multiple versions of the ears so that you can switch them out as necessary.
Here's a vid i made a while back that demonstrates how to build a rigged prop, it's the same procedure, except instead of an animal you just make ears...

Ibis Fernandez | (available for hire)
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Professional Animator, Filmmaker | Creator of the highest quality (modular) G2 rigs for cartoon animator and developer of Toon Titan and Puppet Producer
Author of Flash Animation and Cartooning: A Creative Guide
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