The couple's current rent is similar to ours The sister is has no rental history due to a recent divorce.We're torn given 2 out of the 3 people have lower credit scores and it's not a family moving in.

if it is a BRRRR you'd pay the seller off when you refinanced into long term debt, either conventional or DSCR.i don't know anything about the location, market, etc. but if it needs a 40K rehab, you need to push the purchase price even lower than 140K, or it will not work as a BRRRR. 

Now I agree the 4 will cash flow better than one will but I also look at it from risk of 4 properties will have higher maintenance costs and lower priced properties tend not to appreciate as well as a higher value assetI am also in it for long game and managing one is easier than 4

Balancing that with wanting to do something to maintain affordable housing for those in mid to lower income brackets.  

that we’ve learned in our 24 years, managing almost 700 doors across the Metro Detroit area, including almost 100 S8 leases:Class A Properties:Cashflow vs Appreciation: Typically, 3-5 years for positive cashflow, but you get highest relative rent & value appreciation.Vacancy Est: Historically 10%, 5% the more recent norm.Tenant Pool: Majority will have FICO scores of 680+ (roughly 5% probability of default), zero evictions in last 7 years.Class B Properties:Cashflow vs Appreciation: Typically, decent amount of relative rent & value appreciation.Vacancy Est: Historically 10%, 5% should be applied only if proper research done to support.Tenant Pool: Majority will have FICO scores of 620-680 (around 10% probability of default), some blemishes, but should have no evictions in last 5 yearsClass C Properties:Cashflow vs Appreciation: Typically, high cashflow and at the lower end of relative rent & value appreciation.

Go for a lower downpayment. 

that we’ve learned in our 24 years, managing almost 700 doors across the Metro Detroit area, including almost 100 S8 leases:Class A Properties:Cashflow vs Appreciation: Typically, 3-5 years for positive cashflow, but you get highest relative rent & value appreciation.Vacancy Est: Historically 10%, 5% the more recent norm.Tenant Pool: Majority will have FICO scores of 680+ (roughly 5% probability of default), zero evictions in last 7 years.Class B Properties:Cashflow vs Appreciation: Typically, decent amount of relative rent & value appreciation.Vacancy Est: Historically 10%, 5% should be applied only if proper research done to support.Tenant Pool: Majority will have FICO scores of 620-680 (around 10% probability of default), some blemishes, but should have no evictions in last 5 yearsClass C Properties:Cashflow vs Appreciation: Typically, high cashflow and at the lower end of relative rent & value appreciation.

Payments stay lower, cashflow better and it'll boost your balance sheet not to mention lower risk when things go awry. 

Try looking for lower priced mobile homes on private property that need to be moved. 

Then they lock them in to a SLIGHTLY lower initial cost per kWh.