Hello friends,I am a new BRRRR real estate investor working and living in Germany.Just incorporated LLC in US and willing to buy my first rental property soon, The question here is the "Refinancing" part, As far as I learned that I cannot refinance unless I have a credit score, right?

That will help you remove what’s left on credit and make room to use portfolio/standard or DSCR.When you are not using a local bank or credit union you are going to have to pay the typical origination fee's or points.

However, if improvements were substantial then indeed a Cash out refi will be your best bet, and depending on your credit score, and cash flow you will be between 75%-80%. 

Then the debts are "Omitted".This is usually more beneficial for a person who receives W2 income from an employer and wants to exclude their W2 income from being hit by the credit cards, automobiles or mortgages being paid out of their business checking account.There are also ways to gross up some of the income but some lenders have overlays and hit you with things rather than allowing add backs.

Run a background and credit check on both of them.

Also interest rate has gone slightly down but I am getting an 8.8 % interest rate with credit score of 734. 

Also, I'm one of those sales agents who have never charged my listing clients 6% and as a buyer's agent actually give my buyers a large credit at closing from my side of the commission (must stop once buyer's commissions aren't advertised).

As the home sits right now it will cash flow about $100.00 to $150.00 a month if I self manage it due to tax hikes and the homestead tax credit not applying after it becomes a rental.

There are consequences for our government decisions and a lot of current policy and national sentiment continues to be inflationary (tighter immigration, high tariffs, wars, nationalism/isolationism, child tax credits, student loan forbearance, high government spending/deficits). 

You may encounter a large cap ex hit in the 1st year of ownership before your cap ex money has accumulated from rent and there should be leeway to handle that with some sort of reserve funds or maybe an open line of credit.