As a first deal, remember that it is a journey and experience comes through transactions and relationships you form throughout your RE Career.One of my favorite quotes is that you either win or you learn. 

Keep the relationship as black & white as possible.

Any method is going to work better if you build a relationship with the lender before you even buy it.

This gives you a kind of immediate secondary relationship that might make it easier to start your "team."

The 1 in 50 times where this simple litmus test gets it wrong isn't worth the time suck represented by the other 49 times.Those that WILL drive to your office even though you previously didn't sense any motivation, it is probably worth your time to run a full CMA, offer them coffee, and start that relationship.

I would try to build a great relationship with a realtor.

Build relationships with Realtors, as they are a great source of business for the GCs.

Looking for an agent with experience in investment rental properties that we can build a long-term relationship with.

It's not worth it in the long-term to be unethical as you should be focusing on building long-term relationships, next time the realtor has a great deal, he could relay that information over to you but if you decide to cut him out of this, there's no chance they'll ever work with you in the future.

Depending on your relationship with the tenant, I would consider talking to them in person about it first so the letter doesn’t catch them off guard.