I was given to understand that tenants/tenant lawyers can only sue someone they have done business with.

I have to get a lawyer there anyways and talk about the implication of him doing this without notifying me and redo the loan paperwork .

I don't have any pending legal issues at the moment, but I've been thinking I should find a lawyer that I can go to for questions, to review documents, leases, etc so that I can have confidence that I'm not making any silly mistakes that will get me into trouble later on.

We thought about hiring a lawyer but the legal fees were expected to be in the range of $10k to $15k and would have taken months (if not years).

Each exchange starts the clock again, and you lose the tax benefit if you do not hold and rent out each property for enough time to satisfy the rules.6) I used a 1031 exchange lawyer in the city that I purchased in.

3- Feel free to tag someone who is well versed in DC zoning here whether this person is an agent or a lawyer. 

Otherwise, you could also provide prevention recommendations somewhere on the lease that includes what you've mentioned above.Assuming you don't have a lawyer to help with your rental agreement you can find some sample clauses on a site such as Law Insider.

Quote from @V.G Jason: I'd partner with a lawyer that can help put some contractual language on the downside of working with contractors and real estate agents.I'd also partner with a RE brokerage firm that clearly understands your goals. 

Quote from @Chris Porter: Unfortunately I need to evict my tenants and I need a lawyer.

Anyways I sent him a notice through a lawyer about this issue stating that he is breaking the lease.