no banks, no credit , no W-2, no proof of income needed. 

Probably collecting social security at 62, maybe 63.I have a rental property that is almost paid off (less than 10k away.)FMV: 280.  

@Megan Mason recommend you watch some of the videos from @James Wise youtube channel on S8 evictions.We've been dealing with S8 tenants for over 20 years and they are NOT a cure-all for rent collection challenges.Since rents in Class A & B areas exceed S8 limits, most of your S8 rentals are going to be in Class C/D areas. 

Also, focus on 2 years of job/income stability.Class D Properties:Cashflow vs Appreciation: Typically, all cashflow with little, maybe even negative, relative rent & value appreciationVacancy Est: 20%+ should be used to cover nonpayment, evictions & damages.Tenant Pool: majority will have FICO scores under 560 (almost 30% probability of default), little to no good tradelines, lots of collections & chargeoffs, recent evictions.

Also given the fact that its darn near impossible to get any kind of civil judgement executed and collected on in Portugal. 

This type of loan typically has lower interest rates since it poses less risk to the lender.Non-Recourse Loans: Conversely, non-recourse loans limit the lender's ability to collect from the borrower beyond the collateral pledged for the loan.

there are differences between ESA and Service Pets so I'm trying to understand what are the different proof the landlord will ask

That gives them plenty of time to collect and transfer everything to you.

With a full time job even 15 units gets tough between collecting rent keeping repairs up, preventative maintenance, looking for new deals, managing refinances, etc. 

Based on years of experience with over 530 investment properties in Las Vegas, here are some thoughts to help you evaluate the value of property managers and how to find a good one.The Value of a Good Property ManagerMany people believe that a property manager's only value is collecting the rent.