The boss is firm with it being Wildwood Crest only, very close to the beginning of the boardwalk, and 1-2 blocks from the water.

Anyone have a recommendation on a company for a hot water heat boiler system replacement? 

If there is mold, it will usually be A) on the subfloor exterior, joists, and insulation in the crawlspace, or B) in any areas of water damage/water leaks inside the walls, behind tile in bathrooms, etc.

We did notice some water damage in the front of the house but was told the roof is in good condition.

Of course, if it concerns water, that is an emergency.

Two rentals I have, the water has to be in the owner's name.

If one system malfunctions, you'll be out of the water.

Also utilities and sitework should be less as you do not need to bring in two electrical services, water services and run two sewer services and connection fees.

Is it not problem that they do not have enough water. 

Roll it into the rent with a lease clause that anything over $X is split 50/50 between both tenants and you don't care who uses more water...In short, spend some money and make it a legal duplex or at least make it two separate units.