@Ralph Miller AC is not a necessity.

Start here and research FL statutory and caselaw on easements by necessity

An aggressive split sounds great in beginning, but if you are a performer then a cap is almost a necessity to maximize your share. 

Working with someone that can get you out ahead of the pack is a necessity. 

Having windows is a necessity in my opinion and should be fixed ASAP and not after the tenant moves out.

These 'Micropolis' or mini cities exist all over the US, they are centers of there county and although they are stagnant in job and population growth, they are a necessity for all surrounding towns.  

The agreement can be as simple as to say the 'property owner A' and property owner 'B' hereby acknowledge the proximity of their respective driveways and affirm that neither property has any easement right/necessity over the other.The concern here from a lender/title perspective is the ability to claim a prescriptive easement right.

A surplus could be good because they're spending less or it could be bad because the HOA is neglecting some of the necessities. 

Sort of like wearing two pairs of underwear just in case.Those seeing the necessity for LLC will argue strongly in there value.

It's easier for someone making $100K to save $40K than "average" people making $50K a year to save anything (cost of necessity is same for everyone).