I say look at everything and if you decide to go with a single family home look for something that will produce some income while you live there.

If yes and they produce it, learn the laws regarding this matter in your state real quick or just turn it over to a pro.

Whether you can operate in this manner is irrelevant, because you are considered a business automatically based upon the income you are producing for yourself in this way.

Look for companies that are reputable and have lots of top producers.  

Take a look at the spreadsheet in the link and feel free to ask any questions that will help you decide if it works for you - You don't need to get a new bank loan to buy income producing properties:Average Turnkey Cash Flow Per Door In Phoenix Metro Area Without Getting Bank Financinghttps://www.biggerpockets.com/forums/600/topics/584916-average-cash-flow-per-door-in-phoenix-metro-area

Is there a way to force them to produce the death certificate ASAP?

You could refinance your house to extract the equity you've built and then rent it out to turn it into a long-term investment that continues to produce income. 

Hi, I am looking to buy very old house more than 100 years old but it produce good rental income , is the good rental income is worth taking the risk to buy a very old house , please help me to decide?

@Mayra Perez  being a real estate agent offers you unlimited earning potential, but it takes a lot of consistent action to implement systems that will produce consistent income.

You have reserves put aside which is excellent, the VA is no money down, and the income produced by the other 3 units will give you supplemental income while you establish yourself.