This "parking arrangement" allows you to spend and construct as much as you can during the 180 calendar day exchange period. 

FYI...On March 22, 2021, the Baltimore City Council passed legislation that mandates changes to all residential leases and impacts when late fees may be imposed.Specifically, the law, entitled “Late Fees for Past Due Rent,” provides that “a residential lease shall include a provision that the landlord may not apply late fees to the rent until the tenant is more than 10 days past due with the rent.”As drafted, the above provision is required to be included on all residential leases in Baltimore City, whether or not a late fee is actually contemplated by the lease unless a statutory exemption from the lease requirements applies, e.g., it does not apply to leases for rental units within an owner-occupied residence.If a residential landlord seeks to impose a late fee for delayed or nonpayment of rent, the lease:must include a provision that prohibits a landlord from applying a penalty fee for late payment of rent until:(i) The tenant’s payment of the rent is more than 10 days late; or(ii) The tenant has received the tenant’s regularly scheduled government benefit disbursement if the tenant has previously provided the landlord with written notice that shows the day of the month the government benefit is normally issued or mailed is later than the day on which the rent is due.The Late Fees for Past Due Rent Law, which was signed by Mayor Brandon Scott on March 31, 2021 and becomes effective on April 30, 2021, only applies prospectively to new leases and shall not have retroactive effect on leases entered into prior to April 30, 2021.

Upon the seller accepting the offer they then will try to make arrangements for me to look at the duplexes in order to agree to move forward or not with the sale.

As a condition of our arrangement, he asked that I not attempt to find buyers to avoid a situation where we both bring an equally qualified buyer. 

@example house is $300 K  labor and product estimated $35K.Sales price after Renovation is $400K.Could float the labor for 1.25 to 1.5 times my initial bid for labor.Or some arrangement of equity of same!

I have a good feeling and done due diligence to the extent I think I can but I'd like to know your best/ worst partnerships or any anecdotes that may be helpful when considering arrangements of this type.

The arrangement was o live in a house or property rent free due to me doing all the labor or hiring people .

I have been contemplating this myself for a while.

Is telling me I need proof that I paid him and made any arrangements with him. 

I am contemplating joining exP.eXP and many other brokers have clauses in their Agent agreement stating "Agents are expect to transact ALL real estate business through the Company.