So, the idea is this: If you're making animatronic cat ears, you could put mics in them, then hook them up to a joint to swivel to loud noise. Low quality-mics would be fine as if they turned to every tiny noise that would be a pain. On top of that, you can add some emotion by sensing head movement with an accelerometer. When you keep your head down, the ears drop for a sad look. If you're standing neutral, they stay half-down, and if you jerk your head suddenly they stand straight up to look surprised. 

Could anyone help me? At least with a better blueprint of how exactly to do this?

Thanks! 

Even some ideas would help, or sketches?

It'd be super fun. And, if you get it right, profitable in more ways than one. :3  

I think these would be quite heavy with all the little bits, and probably would require a battery or something. to power it.

 I suggest having a look with google, see if anyone has done this before.

True.

And I've looked around, however I cannot find anyone D:

The software would be very similar to an iPhone, I've noticed.

The only thing with weight is I believe if they were implemented on Furry's headmasks then there wouldn't be much of a difference;I'm not sure, but I think those things are pretty hefty already.