so everyone has different minimums...Hard to say what Mickey's minimum is since it is mostly undefined other than the word minimum, but for me, and for several others, it appears to be a good "quarantine" pond. After all, isn't that what a quarantine pond is supposed to be boiled down to? As good as a good "main" (read bigger) pond but smaller? The question is, can you be happy with that long term Mickey?
So to follow up on the remainder of my minumum "ones"....1 external filter (your choice of type), 1 UV, but 2 electrical circuits. Ooops..
had to have two of something. The liner could be a custom built one after the structure is built, so no folds Brett.
If this weren't a "minimum" koi pond, I would agree with you about the gunite and plaster or other waterproofing of the shot surface as the preferred method.
Add-ons might include a heater to stabilize the temps, but maybe not necessary in Fla, and certainly not on a minimum pond. But I think the stucco or paint might be necessary