I see in the first post you talk about the theoretical energy stored in wood and say that it doesn't vary that much.
Here are some actual numbers to reference (note the values & units are millions of BTUs/cord of wood - so energy per unit volume):
Osage Orange (Maclura pomifera), 32.9 BTUs
Oak, White (Quercas alba), 29.1 BTUs
Locust, Black (Robinia pseudoacacia), 27.9 BTUs
Ironwood (Ostrya virginiana), 27.9 BTUs
Hickory, Shagbark (Carya ovata), 27.5 BTUs
Apple (Malus domestica), 27.0 BTUs
Honeylocust (Gleditsia triacanthos), 26.7 BTUs
Hickory, Bitternut (Carya cordiformis), 26.7 BTUs
Oak, Bur (Quercus macrocarpa), 26.2 BTUs
Mulberry (Trees from the Moraceae family), 25.8 BTUs
These are taken from this blog post https://www.permaculturereflections.com/top-10-fuel-trees-for-zone-5-and-above/
which reference a "a study done by the University of Nebraska-Lincoln Extension, Institute of Agriculture and Natural Resources. I also consulted a study published by the University of Missouri-Columbia along with various other online resources."
I think the University of Nebraska paper might be:
titled: G88-881 Heating With Wood I. Species Characteristics and Volumes by Mike Kuhns and Tom Schmidt
This paper provides the amount energy stored in the wood (as seen above) but lists many more types of wood than the 10 listed above. It also lists some qualitative properties for each type of wood - such as ease of splitting and how many sparks are produced when burning the wood.
I think the University of Missouri paper might be:
titled: Wood Fuel for Heating by H.E. “Hank” Stelzer
Something that the Missouri paper points out is that "One pound of oven-dry wood of any hardwood species has an available heat value of about 8,600 Btu. Resinous softwood species, such as shortleaf pine, tend to average slightly higher at 9,050 Btu per oven-dry pound." Another interesting tidbit from that paper is "On a volume basis, the heavier air-dried wood is, the more heat it will produce. Therefore, a given volume of the heavyweight woods, such as oak or hickory, will produce more heat than the lightweight ones, such as cottonwood and willow." In other words, if you are looking for a greater amount of heat per volume of wood, take a hardwood, but if you are looking for a greater amount of heat per unit weight of wood, take a softwood.
Anyway, I hope these data points might help some in the discussion.