Mystery Object #4 (aka the Suede Thing) isn't rabbit ears, suede pants, a shiatsu massager from Brookstone, an elaborate doorstop, or even this:
"an old fashioned arm/leg rest for 1970s muscle cars that had 'humps' running through the center of the cabin. The two legs would go over the hump. It was heavy so it would stay put."
All great guesses but thanks goes out to Patrick Lee (no relation, but he did grow up down the street from me), who informed me that it's a rabbit ear rear bag used for shooting.
You rest the back of your rifle on it to steady your snipe, like these guys.
My dad was an avid skeet shooter, beretta owner, and NRA member so I figured it had to do with guns.
Thanks for playing and helping me unravel the garage!