Tenant covenants and agrees to pay interest at the maximum lawful rate or eighteen percent (18%) interest, whichever is less, compounded annually, on all unpaid Rent, damages, and other amounts owed by Tenant, excluding late fees, from that date of Landlord’s final accounting until such time Tenant pays all such outstanding amounts.

You will also need a US bank account.

Now I need to find a real estate agent(I am "interviewing" a couple now), an accountant to speak to and of Course a lender.

There are plenty, especially now, that are providing 10%+ yields, and have a long historical record of performing.  

These are features like online renter payments, tenant portal (for payments and work orders), help keeping track of work orders, tax reporting features, and accounting functionality.

Quote from @Sam Wilson: We invested via a retirement account.

@Ashley Kehr I use a combination of Apartments.com for rent collection, RentSpree for tenant and background screening, and Stessa for accounting.

There are also additional costs of operating and maintaining an LLC, like separate bank accounts, annual report filings, tax filings, etc.2.

2) Accountant - Has anyone found a decent accountant with knowledge of REI here in Portugal?

Are you going to keep the separate bank account, keep corporate minutes?