It will help with liability, makes the unit more attractive with natural light, and will make your property more desirable when you sell. 

Finally, any advice on what I should include in the policy to make sure I'm fully covered in regards to manmade and natural disasters?

They have a combined 45 years of experience with rehabs, new construction, and commercial in Chicago so I have naturally learned a lot from them over the years and tend to trust their judgment.My questions - Is 25% down overkill?

No doubt, it's a risk tho..Naturally I would much prefer something with less overhead that performs well, and I'm willing to buy my way into an established market, but then I'm starting from scratch, and frankly despite having some reasonable tools at my discretion I don't really know how to data mine the entire US.Now that the dust is starting to settle after years of being in the trenches with this duplex, it's clear to really make money with this you have to have a portfolio, as I read in an article from this site, 1 or 2 rentals ain't gonna do it.

And naturally, contractors hate that.

Otherwise, I just have a natural conversation with them and learn more about them. 

Suggest you go the electric route--less or  no maintenance costs, and when repair is needed, inexpensive compared to most gas fired boilers or furnaces.I would also have a small natural gas wall space heater installed somewhere on the main living floor (not in bedrooms) just in case of power outage and / or for supplemental heating.  

What is the nature of the LLC?

Since the water supply of the town could never go up there with the frankly primitive water infrastructure of the time, the land was worthless for housing, although it commanded fantastic sunset views of the Gulf of Corinth.But the guy claimed that he had found a natural artesian spring on the land, and that's the land what he was selling.

I may be misreading this, but from my experience of human nature and working with teenagers, if you see this young man as a "punk" or "jerk" and treat him like one, he'll fulfill that role.