A) Just the idea is fun, let alone believing that it may come to fruition.
B) True, the logistics appear daunting! This is a hurdle to be overcome (if it even can be). I'm looking at a multi-level/terrain with barrier walls separating streams and pools. These walls will be more like curtains, not preventing access but view only. I've noticed that the large nerodia ignore very small fish which will allow me to stock the pools and pond with a great number of fry that will not be consumed overnight. The big snakes can then be "hand" fed. I'm dreaming? Maybe, but I love the thought.
C) Reproductive barrier, now that's a hard pill to swallow!
In fact, I choke on this one a lot even to the point of trying to disregard it (banging head on desk).
So, picture this great big solarium, sunny and bright, filled with living plants and running water. Around the perimeter are quarters, separate from but a part of the whole. (This is rather poetic) Trees, standing up to 8 feet tall over crystal water, a mangrove coiled in it's branches [safe from gangs of marauding yellow bellies] ... I could make this rhyme if you wish ...
This is actually making more sense, considering your observations and an ounce of prevention.