I'd like to acquire one for say 60k with a 20% down-payment of 12k.

Columbus is one of the fastest growing markets in the U.S.

One lease is the owners brother which becomes important later on.

. $425k) to purchase a 12-unit Apartment ($1.5M) with 25% down ($375k from the HELOC).The remaining $50k from the HELOC could go into fixing/rehab of the 12-units.Then cash-refinance the larger amount from the 12-units to pay off the HELOC in one lump-sum (as much as possible), then using the cash flow from the apartment to pay off the rest of the HELOC.Repeat the process with a new apartment.1) Does this make sense? 

But I believe this is an up and coming area - my home is one of the first tear-down-rebuilds in the area, with more remodels / tear-down-rebuilds in the works (there are a handful of remodels in the neighborhood).

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?

This will help in determining the fair market value of each asset and facilitate an equitable division.Buyout Agreement: One party could buy out the other’s interest in the LLC and the properties.

This is one of my top 5 pet peeves, as you can imagine. 

Love that part of FL, it's honestly one of the best-kept secrets. 

One extra step to add to all of the good comments above @Doug Webb, make sure you have 1 additional person in your LLC.