Assuming your wife doesn't own another property, I think the IRS will just make the assumption that you were both using this property as both of your primary residence.

I'm basing my initial assumptions on a HML with 10% down, then a refinance at 75% LTV (this is where a market downturn could negatively impact my forced appreciation efforts).

Back in the early 80's when mortgage rates in my area were reaching 16%, just about the only thing that was selling were assumptions.

Of course I did not agree to this as the writing is on the wall, his intension are to stay there for free, and he will likely try and sue me for the deposit after all this. he is also under the assumption he is getting his pet fee back even though the addendum clearly states NON REFUNDABLE.  

As a novice investor, I may be off on the following but my assumption is - low-end tenants are more elastic (i.e., will renew less often) to rent increases since they have less discretionary income.

This is under the assumption that the solar company DOES NOT put a lien on the property, which most do not any more. 

Yes, I am making a lot of assumptions here.

–– what are your financing assumptions?

You really need to talk to a local retail leasing broker there where they can give you insight on cost and process to help give clarity to your assumptions.

They will do their own underwriting and you can pick their brain about their assumptions and if capex is considered when calculating the dscr.