At a technical level you have two paths, either 1) combining the bottom and ground floor units into a larger unit as you suggested above or 2) create a third legal unit.

Happy to share if you're interested.Accounting systems are great: QB, Stessa, Digb but the reality is you want to track a few things at a high level, this will make your life a lot easier when you sell/need to report income/loss, and accounting systems won't always make this easy. 

There has been a considerable amount of foundation work done (addition for piers, leveling, etc).

If this guy is an attorney he should be smart enough to know that top level apartments get hot in the summer.

On wholesaling that is just transactional real estate with income that is taxed at the highest level and to be successful at it one needs partners or access to pretty decent amount of start up money to afford the marketing it takes to get your leads.

It is no different at a high level.  

Look for cracks in the foundation, walls, or ceilings, as these may suggest settling or shifting.Additionally, keep an eye out for pest infestations, particularly termites or carpenter ants, which can cause significant damage to wooden structures.Lastly, be aware of environmental concerns such as radon levels and underground oil tanks, which can pose health risks.Having a qualified home inspector conduct a thorough evaluation is essential.

An approach you might want to take, is to break down each component of the rehab into its own price per sqft/linear foot/units for both materials and for labor.for example you might find that flooring costs and average of $3.50/sqft labor to install + $3.00/sqft for materials X square feet = cost to refloor+ always add an extra 10% for unforseensSo you would just need to do this for every part of the rehab based on what needs to be done and what level of finish you are going for.keep in mind that some things are measured by sqft, like floor, and others are measured by linear foot, like trim, and some are measured by total area, like drywall and paint, and yet others are measured per each like tubs and toilets.A good place to start with figuring costs is The Book On Estimating Rehab Costs by J.

High high level - LLC will typically be an option for DSCR Loans (or bank other types of financing), while conventional will require you to borrow in an individual capacity, but there are pros and cons of each.BRRRR Loans: What Are the Options, and How Do DSCR Loans Stack Up?

I have two local contacts for you Bell-Harding (HBI) is a local high level CPA specializing in Foreign investors and these scenarios.Another would be Daniel Boyd a local cost-seg specialist 407-451-8996Best of luck