Basically from my understanding , Uncle Robert doesn’t believe in 401K and suggest that it’s better to just invest in REI and control my own destiny rather than the bankers and wealth managers in Wall Street that gambles with my money 💰 if I participate in a 401K program.

Before you consider the above accurate in your state, find an experienced attorney who specializes in MHP leases.  

Remember that you want to find a deal that cash flows from Day 1 (with the exception of building in house hacking one unit where you have decreased rent), otherwise you are gambling on appreciation.

If I purchased a SFH for $30k I would be very happy.Along with that you would need to make sure that your cash flow calculation is accurate. 

I am trying to be as accurate and realistic as possible and certainly don't want to buy a house just to buy a house.

In reality, this is not going to be accurate.

Given the age and lack of amenities offered at these buildings, $750/month might be more accurate meaning that after complete renovations, this portfolio could gross $13.5k/month and $162k annually. 

The diversity angle alone cannot accurately assess the viability of your venture being successful.

I'm worried that I won't be able to accurately predict the total cost of this subdivision project.

It will help in presenting accurate info to a lender and will only increase your credibility.