Here these old foundation are around 3feet wide of rocks and other materials I don't know the name of in english :P .

I second @James Carlson has great info on investing, the laws leave it wide open for Airbnb. 

Your insurance policy should fit your needs, not the insurance carriers requirements.Look for a commercial insurance broker who can offer a wide range of insurance carriers.  

@Andy Bartley - Most of our content is nation wide.

We have an extremely diverse array of positive economic drivers that yield stability AND growth, and virtually no permits to build units that rent from $650-$1000/mo.... keep in mind, we're still able to find 7 and 8 caps, with value add potential due to below market rents. 

Brian:Security deposit laws vary widely by state and municipality. 

None of these had an early payment penalty.The next quesitons are, how long until you can refi after your aquisition of the property, and will they refi for an investment property held under an LLC, and again, answers varied widely.

I've built a 56" wide closet in the MBR of a rental.

The DC area has a HUGELY wide array of price points. 

You have two options there, buy a pre-hung double door (solid - no glass) set and install or frame in the opening to a standard 32" or 26" wide door providing more wall space in the bedroom as well as the room outside the bedroom!