Or do you have to use a 3rd party site to keep them updated and then spend more? 

I'm not familiar with the market or the legalities of wholesaling Florida.

Do I have to legally disclose to my boss that I will have my sales agent license and have a brokerage sponsor that is someone different outside the MF development company?

Make sure to verify any information from a party that doesn't have any advantage of you getting their services before making a decision.  

Best part is that unlike the old UPREIT that triggered a tax if the initial property is sold, today’s structure is immune.

Looking for help and suggestions- I want to say I have learned my lesson and now know to use a third party to hold funds.This is my first time working with a private lender/family member.

If the purchase is done in cash, as you mentioned, they’d have more flexibility, but they’ll still want to carefully consider the tax and legal implications of the subsequent sales.I hope this helps, and good luck with your client’s deal!

As you are partnering with your sister, have a legal document drawn up as to what happens if one of you wants to sell and the other doesn't, how expenses will be split along with money you are putting down, borrowing, profits, etc. 

You will want to consult with a lawyer.In regards to your last two questions here's some background on what makes a contract valid and enforceable:Offer: A promise to do or not do something within a certain time period Acceptance: A clear and direct statement that all terms and responsibilities are accepted Consideration: A legal and adequate inducement given in exchange for the promise Capacity: The parties to the contract must have the legal capacity and competency to contract Awareness: A party must be aware of the contract Legality: The contract must be legal in the jurisdiction it will be operating in***Not legal advice*** Steps I would take: -Review contract in detail to understand each counterparties responsibilities (if you are not aware)- Email a copy of the lease to each of the tenants listed on the lease and reiterate lease expectations for termination notice, rent payment etc. - If the lease was signed via Docusign (other esign may have same ability) - you can go to the envelope, go to history and view the IP addresses for each action taken.

Just a worthless piece of paper that validates a promise (legal obligation).