The solar system adds no value to my property for rental purposes, and I may even be ripping up the roof & replacing it in the new year.Beyond sending a nasty letter through my attorney via certified mail, demanding the company come pick up their equipment, am I required to take any further action or fulfill any obligations regarding these contracts?

Quote from @Dan Grove: Some combination of cash to seller, closing costs, repairs, construction, paying off arrears, assignment fees, commissions.   

It demands effort and persistence.

Your wife as conservator/guardian has an obligation to her mother and selling the property to herself creates a conflict of interest in that she stands to benefit as the buyer and is also making decisions for someone else as the seller.2.

Meaning you may be able to do some cosmetic or smaller renovations like bathrooms or kitchens in your duplex when the tenants turn over and those smaller investments can demand higher rents, so in the longterm you may have more cashflow from the duplex to help fund a future investment in another property while you wait for market conditions to change.

It's a combo of low housing supply, higher interest rates vs. seller expectation, and a poor economic outlook for the country.As an investor with a few rentals it's like like the parking brake is stuck on.

They are more motivated to get the seller to sign with someone without an agent because they get more commission.

You would expect a clean title at close so if there is some issue, then either it would be resolved by the seller or the deal would fall through.

I don't know why you would think a tenant requesting notice before you accessed the property would be an "unreasonable demand".

., focusing on markets with strong demand or finding value-add opportunities) can yield long-term wealth.It really comes down to your goals.