Exactly what I would do!

I'd pet them all. If they growled at me in a friendly manner I know it's mine...
I accidentally taught him to growl at me when I was younger, somehow

Call their name?

Say mommas home

Shake a pill bottle and see which one gets excited.

Command "stay" and the one that goes flying into a wall is my girl.

Easy their would only be one, cause my dog kills everything she see's :D

See which one walks into a wall while trying to run to me

My dog actually snorted and sneezed when we walked through the door. We have no idea how it happened. We had thought maybe she was trying to smile at us because she thought she was human.

My newest dog’s tail would be wagging. In a circle. She does like this helicopter thing with her tail.