I'm also concerned older homes have already seen their biggest jump in capital appreciation and don't have as much potential for price growth compared to newer homes.What are your thoughts on older homes?

Hey Isadore, Send the tenant a notice of non-payment and have the tenant go down to their local public housing authority office, HRA, or Department of Social Service office and provide them with the notice.

Housing is still affordable compared to other markets, which keeps renters and investors coming.

With 40-60K in equity you could explore selling to reinvest but it depends on what deals are out there compared to yours

Since you can't control the sale price, you basically have a $4k cushion to your reno costs, or otherwise you lose money compared to the as-is scenario.

Commercial programs a heavily dependent on location and NOI (less one size fits all compared to residential). 

In the Bigger Pockets free book, "Real Estate Rewind", as one of the 11 co-authors I wrote about one such Tax Sale purchase and made money but not enough money to warrant the risk involved.

How do the interest rates usually compare between the two?

Using a Whole Life Insurance (WLI) loan avoids banks but accrues interest, potentially reducing policy benefits—compare this with other financing options like HELOC or seller financing.

I think you should start by understanding what it is your investors want out of the deal, analyze how the returns compare to traditional investments, and then see where you fit into this deal.