What about the trend line here in red?

Seller financing will probably be your best bet

As an aside, could it be subdivided where each property would meet current setbacks from front/rear/side lot lines?

A lot of the other numbers they provided seemed a bit out of line from what I would typically expect too, the water testing I’m not familiar with and though I may get some good guidance as to whether the costs seem right or not.

I'll bet 99% would agree with rounding up as a no brainer, effortless way to avoid unintended delays.     

I would also check your comps in rent say go back over the last 5 years and I would bet you are seeing over time increases to your rent in your area due to growth?

I am willing to bet that a house of that size with a Koi pond is in a fairly nice area that’s zoned residential, single-family.

Your best bet is to find your own agent.

While some other NW neighborhoods might be hotter or have higher upside, I feel sticking near Blue line stops will help minimize risk. 

Also I strongly urge you to file a complaint on line with the Attorney General in INdy it takes five minutes and you can do it on line..