Nasty customers; but pretty much vanilla flying creatures.

They do have a ranged attack; not really sure how to represent that. Maybe it should be a mechanic for the set; actually - lots of creatures and weapons have "Swing or charged swing" options. Maybe use exert?

Funny name though.

2/4 flying for seems a little strong.

To be honest, there are some creatures that you don't really need to spice up if you're aiming to structure this like an actual set. I don't think these guys are particularly memorable at all to warrant anything special being done, but Exert works well if you want to focus on swing/charged swing. Careful about mechanic overload, there's a lot of various mechanics that could/should be represented in a Zelda set and focusing only on the most popular/resonant ones should take priority over adding random flavor bits for accurate representation of everything represented on a card.

Certainly doesn't look like it should be able to fly, armor and all

It's more like huge jumps. And Aven get away with lots of armour.

The in-game art is, um, about 8 pixels high and monochrome. So no help there :)

Currently it's pretty much Updraft Elemental which in itself is quite an upgrade over Horned Turtle.