I've been knocking on doors, there is one that seems like it's abandoned, however despite finding the owners name from tax records I cannot seem to get in contract with them to make an offer (despite trying x, y and z). 

Have you passed the tax assessment yet, or is this your first year of owning it?

An ITIN is often required for tax purposes when earning rental income in the US as a non-resident.Please feel free to PM me with any questions. 

He is busy working at the hospital and doesn't want to deal with tenants, toilets, taxes, trash, and all that haha

So you are able to get the cash flow, tax deductions, etc.

Most Florida markets will share some dynamics though like taxes and insurance. 

Usually the numbers don't work to build in these neighborhoods, unless government tax credits, etc.Do you see the problem with your two statements:"The turnover costs could/will be high"and"How much more damage could they do?"

What are the tax ramifications of a sale, if any?

But I read that there's downsides in doing that just don't know exactly what- capital gains tax, etc. also I was told to open up a new LLC and use my current LLC as the manager.

Pretty much think of a commercial loan process as a residential loan process backwards.Lenders do go off the income of the property, but they also do check out the purchaser...3 years tax returns and a personal financial statement.