I'm not sure what to think of your post. It sounds like there should be something drawn to a pond on a farm...no need to go collecting "Massuanga" snakes and the likes...but good luck finding two of each anyhow
Imagine how rewarding it will feel to find you've helped create an environment that attracts snakes and frogs....and then compare that feeling to the knowledge that you've just marked a few pairs of beautiful animals for death by relocating them to an unfamiliar location.
Wait until July, and then tell us how many naturally occuring frogs you've found in your pond! Trust me on that! lol
But good luck field herping anyhow! Bring a camera, not a pillowcase!