Vapor permeability and material suggestions for humid temperate climate

Just because they're telling you how to do something better doesn't mean they are pushing it as "best practice".

Blower footrests are fine and performance is vital. The problem isn't the what it's the why. And for me the why is a healthy structure that promotes a healthy environment for the people and things inside. Who care how well it performs if it makes me and my children worse in life?

@Brian Knight

Because I am a laymen in terms of building materials, I approach the airtight and draft proof terms as a matter of connotation versus denotation.
For me, the term airtight as used is jargon for the industry - but what it implies to a consumer is a bad end result but the terms "draft proof" or "draft free" and the like implies a good end result.

As a bad metaphor - if I place a plastic bag over my head and duct tape the opening around my throat - I may indeed have an airtight envelope - I can still breath, but I am still breathing only the air sealed within the system.
Now (after removing the plastic before I pass out) if I have an over-sized alpaca hoodie on, big arm hole and space for my belly - I can duct tape the four holes and seal up the draftiness - and yet, still breath fresh air and stay warm.

The implications - the connotations - are very negative for the term "airtight" with respect to living beings whereas there are no bad connotations or implications arising from the terms related to being "draft free".
It is simply a matter of perspective.

One may feel comfortable sleeping in a coffin, but not for very long if it is sealed.
Just my half pence worth.

with the arkansas winter sun you can surely supply all your heat, probably even on cloudy days.  the whole trick is to get the geometry right with overhangs so your south facing glazing is fully shaded in summer and fully exposed to solar radiation in winter.  if your winters are cloudy, just go for more glazing, maybe 60 percent of the south wall surface., and a way to insulate the glazing, like sliding walls, insulated curtains or the like, or make it a separate glazing wall outside the exterior house wall, but with a roof with overhang and doors to open to the inside.  I am originally from southern MO and when  I occasionally dream about building something there, I think like that, slab on grade, with  deep perimeter insulation, (that step taps you into a thermal mass that tends to the average annual temperature) long on the east west axis, lots of south facing glazing that is fully shaded in the hot months, straw bale exterior walls (bales elevated from slab) and cob or masonry interior walls, shade house on North side to let in cooler air in summer, light colored or reflective roofing, And of course careful attention to keeping it all dry. maybe this is just basic stuff, but hopefully helpful to someone.  We heat our house entirely by the sun even on cloudy days here from april thru most of october(we need heat year round), with a max summer sun angle of 54 degrees.  its perfect in april and sept/oct, in the summer we have to open windows to spill some heat and in winter we have to burn wood.  I suspect your winter sun angle is not too far below our summer angle, and probably very close to the spring/fall angle here.
I think koppen climate classifaction would actually call most of arkansas 'humid subtropical' https://en.wikipedia.org/wiki/Humid_subtropical_climate
if the average temp of the coldest month is above freezing.