Hi,
In my opinion, this type of setup would be great for axolotls, providing there are neither fishes (no kois) nor herons.
Now, the temperatures could be more problematic (search for "Tulsa climat" and "Mexico climat" and compare the charts),.
Lower winter and higher summer temperatures in Oklahoma than in Mexico.
I have a similar project (within 2 years) but I live in a more temperate area, where I know axolotl can successfully undergo winter outdoors.
yes, if i were to build an axolotl pond it would be species-only, save for possibly a few snails or other creatures that might sneak in via plants. as for the herons (and any other predatory animals) i would have to either have a "scarecrow" of sorts or some kind of netting//cover.
temperature has been a big consideration in all of this, i've written about it some in my thread titled "sanctuary + breeding facility."
i would go about temperature regulation by having deeper water, lots of shade from surrounding terrestrial plants, as well as free floating plants in the pond itself. obviously, this doesn't account for extremely hot temperatures, in which case i would likely need to round up all the axolotls and house them in temporary tubs such as the one pictured below:
this would also be a good opportunity to check over all the animals and record any growth, injuries, illnesses, or other changes. i plan on doing this a few times a year either way.
winters, i think, should be much easier to deal with. i've read that axolotls can do fine under ice, and i would probably install a heater during especially hot days. again, if the weather proves too extreme, i would collect all the animals and tub them until things return to normalcy.
i'll include more pictures of pond setups i like in another post, with commentary on what i would change to optimize it for axolotls.
thanks for the read and reply,
-ren