Consider adding motion-detecting floodlights and installing visible CCTV cameras around entry points to deter crime.

Screwing a 4x4 screen into a roof would probably not show up as an "installation". 

or "Could I see where you have installed these units?"

Consider an Installment Sale: By structuring the sale to receive payments over multiple years, you can spread the capital gains tax liability over time, potentially keeping you in a lower tax bracket each year.11.

So we went directly to Lowe’s, who provided a receipt for microwave, installation, taxes, etc. totaling about $530.

I would ask the installer to come back and fix it.

Are you installing new smoke alarms?

You were upfront about there being no vent and needing to use a ventless option, so you don't have to install that for them or even split it, but splitting it probably is somewhat fair. 

Typically you can get a window egress installed for $3k-5k.Not aware of a Metro Detroit city that will allow the conversion of a SFR to 2-4 units in an R1 zoned area.- You can improve your search by only looking in R2+ zoned areas.- Will still be challenging to acquire a SFR at a low enough price to justify the cost of any conversion.Regarding Michigan property taxes, we have a one-page explanation document we'll share if you DM us. - The challenge in Detroit is that the city is "deliberately" keeping SEVs low to not scare investors away over property tax increases.

My neighbor did this during one those programs (had a 2 family, made into a legal 3 family by converting the basement) but, among other things, he had to install a fire suppression system in the basement, expand windows for egress/ingress purposes, and do a whole bunch of other things.