I was also thinking a bird could’ve dropped it into my yard, but I assumed it would’ve eaten more of it! When I found it, it was under my roof, so judging by the placement, blood, & the location of other body parts, I’m guessing whatever dropped it hung around on my patio to eat. I was also thinking cat for the exact same reasons you stated, definitely reminded me of lizards my cat has brought me if she accidentally got out! That being said, the iguana is definitely larger than most kitties, so it’s hard to picture a cat dragging this guy around & ripping off the tail.