Are they hosting open houses, networking with neighbors that might know someone, promoting the listing for the reasons you listed? 

In declining his offer I would go ahead and set the expectation that you are granting him a promotional rent for this lease period only  and he should expect a rent increase at lease renewal.

I’m seeing that some investors advocate for higher end materials when you can-granite counters, stainless steel appliances, tile bathroom.

Because of material participation I can deduct that $350k vs other income.Using combined federal and state tax rate of 40% x $350k = $140k in immediate tax savings.

Because all these new construction homes were either started or finished during high inflationary times in regards to both materials and general real estate.

My guess is materials from stores like Home Depot or Lowes.

I self manage, have material participation status and file on a schedule C.

Its handy for me to store maintenance materials, lumber, vanities, applicances, etc, for my other properties.

The number one thing I tell fellow investors is that in the city proper you will deal with 36th district court and that has a material impact on the speed with which the court process will proceed if you need to evict. 

There are still materials and maybe some other specific trades, which you and your sons may not be able to do.* Ask that same real estate professional above, if it is worth doing the rehab, if you decide to sell?