The tenant can then use the savings from not having to pay rent to get other accommodations until they can return. 

If you want to give him another chance, send him the letter and also add in that if you don't hear back from him with a day or two, you will be sending him your notice of not extending his lease.And I am sure someone will tell us why this isn't a great idea, but you might even consider trying to find another accommodation for him.

Tell the lender what you want and if he can't accommodate, find another lender. 

If listing agent cannot accommodate, try to have your (buyer) agent get tenant contact info and set it up directly. 

Local community banks or credit unions can be the most accommodating and local bankers usually want to help people they live close to.

You can add stipulations to any agreement to make it accommodate your needs and because any commission paid on a listed property is paid by the seller, it is certainly worth enlisting an agent to help with acquisitions when you aren't getting enough opportunities with off-market homes.

Yes but recently Airbnb said the trend is visitor looking for more budget-friendly accommodation.

Tenants in DC are very knowledgeable and will report you in a heartbeat to RAD, (rental accommodation division) and to DCRA.

A steeper curve generally indicates more economic health (demand for long-term borrowing), an accommodative federal reserve,

Let him know that he will have to accommodate showings till he leaves.