With regards to "red tape" I'll tell you that the week after we closed on our property we received a letter from the historical society welcoming us as new owners, but they also informed us that any work done to the exterior needs to be approved by them first.

Does anyone have any experience buying rentals in Spain as an American?

She then explained that being african american, she had not been able to obtain a rental; she had lived at her last house for 3 years never late on a payment.

What I have been seeing is that current estate planning is NOT serving modern society and families.

The vast majority of Americans have no idea what real struggle is like.

Has anyone used American Rental Managers for their property management? 

Per this NY Times article, the average American knows around 600 people.https://www.nytimes.com/2013/02/19/science/the-average-american-knows-how-many-people.html#:~:text=The%20average%20American%20knows%20about,do%20you%20know%20named%20Kevin%3FPer the US Census Bureau, the average American moves 11.7 time in their life, which based upon an approximate lifespan of 84 years, works out to be about every 7 years.https://www.census.gov/topics/population/migration/guidance/calculating-migration-expectancy.html#:~:text=Using%202007%20ACS%20data%2C%20it,one%20move%20per%20single%20yearSo, if the average American knows 600 people and they each move about every 7 years, that means that the average American knows around 85 people that move in any given year.How many of those moves do you want to be involved in?

Even the wealthy community of Lake Naomi nearby is having serious problems recovering property values.https://www.reuters.com/article/us-usa-housing-underwater-insight/millions-of-americans-still-trapped-in-debt-logged-homes-ten-years-after-crisis-idUSKCN1LU0EP

Given that I do not have any American credit established, the technique of assuming a mortgage is very attractive to me.However, my concern is that will I be eligible to assume a mortgage given that I am not American?

Since Paraguay is a neighbouring country to them and they'll know it much better than Americans, speak the same language, have a similar culture and legal system, ..., if Argentines won't invest there, I don't see why Americans would.It's great to be ambitious but sometimes (if not all the time) you have to learn to walk before you start to run.Hope this helps