Standard kitchen counter tops are 34" or 36" tall. 

The floor joists should be 8” tall as a industry standard therefore the mass majority of your ceiling would then by 7’-4”

Since you're new to the area, you might not be aware that Brevard is about 70 miles tall.

And then he answers it, “As tall as it possibly can.” 

Its about as tall as a push broom.I think it’s mostly use to clean up mud and stuff but it gets the staples out. 

Biggest issue is the jacuzzi has this weird platform that make a step about as tall as my knee to get in.

Doors are usually 6'-8" Tall.

Build a fence that is as tall as my house on my side of the property line facing their house of something solid - concrete block perhaps, with rebar reinforcement, or similar - and then screen off your side of it completely with some tall greenery such as Emerald Arborvitae or Thuja Green Giant.

My knee-jerk reaction is like others "nope", but then take a minute and think on it, because it's realized this is the tenant sharing a problem at the property, and ask what results that could make. 6' fence is fairly tall as is, so issue isn't height, it's that it's so easily scalable.

Louis every time a sale is made, and there are multiple exterior code violations as we speak, such as the grass being 2 1/2 feet tall, a live wire hanging off the garage in the alley, shingles falling off the garage, the garage being abandoned and derelict, and bricks literally falling off the front porch.