I am not sure the appeal of radiant floor heating will be worth it, at least in my area.The warm-air gas furnaces seem to be cheaper than the hot water boilers, however, boilers seem to last longer.I will not be running anything through the firewalls. 

My insurance company wanted to see a firewall in the attic between the units.

The objective is to erect firewalls around the equity, both explicit (insurance, entity structure) and implicit (murky, difficult to trace ownership).

So I believe that is a firewall.

Seems like there would be a whole new set of hassle with the city and the building codes,sprinklers, firewalls parking. elevators.I looked up Key Homes, they buy in Jacksonville.

For example, we are finishing our basement to make it a separate unit and there needs to be a firewall between the basement and the main house (basically 2 layers of drywall).

Retention systems, fire sprinkler systems, firewalls, fireproofing, etc.Your land should be no more than 15-20% of your total project.

Otherwise you do have to disclose your interest in a trust if a lawyer asks under oath.You need an LLC or corporation to create a firewall when it comes to liability.

There are specific requirements dealing with fire protection, fire resistant construction (fire walls, etc), egress, and other things. 

Mine did, but the driving factors for me using an LLC weren't to avoid liability over payment for asset as much as attempting to place a firewall between my personal and business dealings.