But you're talking about  partnership with three people, different ownership interests, and you're talking about retaining control which would be manager-managed.

CAN I retain rent from her security deposit until it is release? 

ASSIGNOR RETAINS THE RIGHT TO ENFORCE THE PURCHASE AGREEMENT: Assignorretains the right, prior to close of escrow, to pursue any and all legal remedies, if necessary, inthe name of Assignor to enforce the Purchase Agreement.

This gov’t entity actually has actually suggested that we become contractors for them, so that they can pay us directly to retain the property for their traveling employees.

Once they know you mean business they will give you the deals to retain you as a loyal customer. 

I would have put in the purchase contract for the house to be delivered vacant, or retain some amount in escrow to cover costs of eviction/repairs/damage/etc

This would allow you to retain complete oversight of construction, helping control the value chain and mitigate risk.

From information provided, he is involved in two, not four.Nothing in this thread constitutes tax advice and taxpayers should retain their own tax CPA/EA if they feel uncomfortable with Sec 199A or DIY tax returns in general.

But a REIT is not really different than any other type of real estate fund (invests in pooled assets), with again the difference being REIT taxation and how it must distribute percentage of profits and cannot keep as retained earnings. 

Something I would advise as well is to remove the specific performance remedy from contract -- the Seller should be agreeable to only receiving the earnest money as a default remedy and still retain the property to sell to someone else.