Wetlands will be delineated in large areas but unless you get a wetland specialist to give you a wetlands report on the specific lot its still not that accurate.. you may have one you may not.. but again if you have standing water Bull rush's and other wetland type vegetation its easy to determine.. if your looking to split the acreage up.. the country is going to make you do all those reports anyway. 

Our tenants in SFRs are responsible for lawn care, edging, flower and vegetable beds. 

Well, the mold hyphal matter (the spores/seeds, branches, etc.) have the allergen in their proteins.  

I have a modest income (I'll make just under 60k this year) as a Vegetation Management Arborist.

A B&B style house might be OK though.There's also agricultural things you can use the land for like timber harvesting, growing fruits/vegetables and livestock grazing so even if a vacation rental wouldn't work it might be possible to rent the land for agricultural use. 

At those levels, many of the proteins have dissipated.

We renovated the front and back yards to put in a new lawn, irrigation system, vegetation, and privacy fences.

The critters eat fat and protein (food and pee).  

A vegetable garden all dead, with 10 extra yards of dirt that had to be removed.

The rental I have is about 1200 sq ft-one level and I have one for the whole place.Like you, I have furnaces in my home (and another rental in a colder area) and prefer those.for the mini split, you need to keep the outside free of vegetation and change the filters.