I stuck my flag in the ground and staked my claim.

American School of Business 

if i invest in a property in america from out of america can i take a loan from an american bank or do i have to take one from a bank in my country and to get refinanced can i use an american bank as a foreigner.

I told her in the spirit of @Frank Rolfe "Don't be put off by the beach towel (in one case it was a Confederate Flag in Park #2) as the curtain" and told her it's by God's grace she doesn't have to live there.

or are there better ways for non americans to invest in properties in america or is the 500,000 usd route better to get residency in america to qualify for american mortgages 

@Toby Jurging we have mostly used NASB, North American Savings Bank, Jason Zook is the loan guy there.

I'll tell you from experience foundation problems are HUGE red flag.

I am looking to invest in the US but i dont know if there is any loan where a person who is not american to get a 20% down payment and a 4 to 6% intrest rate.

While we don't know anything about the specific lender you're dealing with, there are enough red flags in what you've posted to be suspicious. 

There is also the dilemma of 40K being deposited into my bank account and being a red flag.