My first suggestion would be to make the mask out of boxboard (like cereal boxes) or cardstock (you can gluestick the construction paper to the cardstock or boxboard backing, if the construction paper is important).  That way you start with something fairly sturdy.

For the ears, unless there's a reason they have to be very thin, I'd probably reinforce them with popsickle sticks or something wooden rather than wire-based.  If you need them bent and reinforced, then wire is your best bet. 

I find that doing a single layer of paper mache over a cardstock armature and letting it dry helps make it sturdy enough to handle the subsequent layers.  I dry mine in front of a fan on low and it dries within a day, sometimes faster. And if you're using flour as part of your paste, that dries pretty hard, and will reinforce the construction paper.

The thing will be to either prop up the mask or stuff it somehow so it doesn't warp while the first layer is drying.  Would it be too crazy to think about building 2 masks out of cardboard?  The first you stuff with newspaper and tin foil to make it a sturdy base, and the second is your real mask, which you coat with a layer of paper mache and then place on the first mask while drying to prevent warping?

The faster it dries, the more it warps, in my experience, so letting it air dry or in a light breeze can help.  Some pastes warp more than others, and it's been awhile since I used flour, so I'm not sure if it's a high-warping paste or not. 

Stolloween (stolloween.com) uses flour as a main ingredient for his paste and builds over boxboard armatures alot, so I'm guessing it should be ok. 

Good luck!  And let us know how it goes. 

-- Beth