I read all 8 articles and i agree with pretty much all of what you said (the numbers made it alil complex lol). My view has been if (example) an anole needs 5 gallons of space,( lets ignore the geographical are rule for a sec), an american toad needs 10 gallons of space, and i have 3 toads and 2 anoles. I would keep them in a 55 cage so they have some cozy space. What are your views on this?
The problem is that this oversimplifies the issue as the volume doesn't tell you anything about whether those areas are really good for the animals or are they just "making do" with suboptimal conditions. As an extreme example, you can have a volume that is one inch high, one inch deep and 1,155 inches long (there are 231 cubic inches in a gallon) but obviously the volume in this example is unsuitable for the animals. This is the other side of the coin when recommending volumes as a method of determing spatial needs. In reality, the spatial needs are determined by the resources required to ensure the behavioral and metabolic needs of the animals. As an example, the anole requires a basking site and ideally some UVB (to allow it to behaviorally modify it's D3 stores) along with the dusted food items, perches that allow it to move to regulate it's body temeprature (if you have the UVB source and the heat lamp close together, then the anole can get UVB damage from overexposure), the perches need to dry out between spraying or the anole can get fungal infections, and there needs to be a way to feed the anole. The toads require a damp substrate, an ability to get away from over-exposure of the UVB light, and to avoid the extra heat from the basking site of the anole. We can go on with the discussion of the niches but I think you should get the general idea.
The other thing to keep in mind is that when discussing success for a year is that the life span of some of those animals in captivity can far exceed that with even modest care (some Bufo species can live for up to 40 years or more (check out this site
http://www.pondturtle.com/lfrog.html (even though they are highly outdated the data is still relevent to this discussion)) and even Bombina can live for more than 20 years (I've worked with them that were well over 15 years and were originally wild collected animals).
In general, it takes a lot of forthought and knowledge to put together an enclosure that allows the animals involved to live a long and good life and is something that even many of us with a lot of experience don't undertake lightly.
Some further comments,
Ed