In return, I told him that I would be his company's energy consultant for free.

Yes it would certainly be worth wild to consult an attorney to see what your options are. 

I'd like to remove this doorway and the small amount of wall around it to open the kitchen up to the rest of the house.I know that it is a bad idea to remove a wall without consulting an expert, but I'm not exactly sure who I need to talk to about this.

Im not an attorney - maybe pay for a 1/2 hour consult with a local attny. 

It is agreed that, the undersigned is acting as a principal and either: A) had no dealings, negotiations, or consultations involving the Property with any broker or agent other than C&W or B) will be responsible for any fees or commissions due to any broker acting as the Buyer’s Agent and neither C&W nor Seller shall have any obligation to pay any commissions or fees to any such broker.

I would learn about the real estate laws in your area and/or consult an attorney to find out the proper procedures regarding the late payment.

Always consult with your attorney before you rely on the above information.

@John Underwood, I definetly agree with you, but after I consult a lawyer, they told me the dog has showed propensity to bite, since I am also aware, if something happen, The landlord can also be sued.

I would honestly pay for a 1 hour consultation with a local real estate attorney and also with a tax professional.

I would definitely consult with a qualified Attorney to see if it could be structured correctly and what the costs involved.