the goal is mold avoidance and air quality from what I can gather and not full humidity mitigation per se.
Don't have a sense of your budget.... but...
Were I in similar situation ground infiltration would be a priority concern and ensuring breathable walls rather than air tight. Breathable walls also starts in the foundation. Appropriate water diversion, crushed rock, locking wall in footing with external perimeter (internal if necessary) drains. Using Magnesium based cement as opposed to portland would also be a priority and if steel re-inforcement needed then again- use Portland but minimize its use and use Magnesium layer over the top. You can also get prefab magboard for flooring and walls.... Cement doesn't have to 'wick' water....But Portland cement certainly does. Mag is great for avoiding mold. Fibers/woodchip mixed in mag cements to spread the dollar, increase the overall mass to approach the costs of Portland cement won't necessarily increase mold risk either in the company of Magnesium.
Insulation wise hemp batting and hempcrete would probably be my priority considerations for mold avoidance along with natural wool, though some natural wool will be treated with chemicals to increase the pest resistance. These are currently pricey options (the hemp wool wouldn' tbe so bad if not for the shipping as there aren't a lot of places to get it from). Strawbale shouldn't be avoided for purposes of mold so long as you seal with clay/lime plaster... Testing supports that any potential mold growth does not impact indoor air quality on testing with these methods.
For any interior wood that doesn't need to be 'shown off' you can paint with nontoxic primer (easier said than able to find)/kaolin clay 50:50 mixture to avoid mold growth. Not sure how I feel about naturally mold resistant woods as they often are aromatic and have their own natural volatile oils than can be an issue for some people sensitive to chemical irritants (I do love cedar myself.... just don't know about living in it long term).
You will not escape mold completely from your environment... and sealing all the indoor air pollutants into your home to avoid external mold is probably a worse idea.... so yes, good ventilation and opening windows for an hour a day... and not having any of the core structural materials with some level of permanence being food for mold is generally a good idea....
