Now the tax assessments can vary widely, I’ve seen land value as low as 3% and as high as 65%!

The reason for the seller's willingness to discount that much in today's climate, from what info I have so far, is due to the extremely low rate on the modified loan (less than 2%, recast for a new 30 year term).So due to the rate, even at 50% of UPB, the return on my investment would be around 4% after considering servicing fees, etc., which is not nearly enough to interest me in this deal, considering the risks of borrower re-default, etc. 

You'll probably need to go with a low down payment program like FHA. 

We are also losing out to cash offers since our price point is low (under $150,000 in south Florida).

The plan is to only go for about 1 year.My thought is that I would like to have about 3 houses rented when we move to Central America, but some say refinancing out of such a low interest mortgage is not a good option... but that's why I'm posting to get your thoughts.

I would be very leery of doing this size deal long distance with those low rents.

Low prices commercial or residential

I've seen seasoning periods as low as 30 days (Rare and more expensive) But typically it is a 6 mo to 1 year requirement 

Get as much as you can from the buyer to benefit the seller, not yourself.But if you are another scammer wholesaler and trying to get the property for as low of an amount as you can from the seller and take as much profit that you can scam out of the deal, then you are the typical wholesaler and should not call yourself a broker. 

The BRRRR strategy is usually used to get your initial investment back but it is necessary to purchase the property with equity built in, otherwise, the typical low down payment house would take around 5 years to reach the 20% equity mark.I would recommend reaching out to @Amber Gonion and her husband Rick.