I would appreciate any advice on what to do.I can't add anything except to say: hey, that's really hard and I'm rooting for you. 

The right thing to do would be to get on task to finding the root cause of the problem and addressing it.

And if you are having trouble finding housing that is a positive for me because you may stay in my property longer.Other considerations: prefer non-smoker, how long you have lived in the area (deeper roots/ties to an area are a positive), income compared to rent, how long you have held current job, how stable your overall job history is (changing jobs yearly is not a great trend), how long you have lived at previous addresses (frequent moving/turnover costs landlords money), what Facebook profile says about you (pets, drama, responsible, crazy), what prior landlords say about you, etc.It's a shame that some lessons in life are so painful, but hopefully it ultimately leads to you being stronger and better for it.

Tenant has roots in this part of town and had to move due to unfortunate events (plumbing issues + mold).

Rather than going to the root right away, I talked to the other tenant to confirm that there was something going on.

Just like any other sewer line issues, if it is general wear and tear/tree roots/etc. landlord is responsible. 

Medical problems and a prior ex running off with all the family wealth were the root causes of their problems. 

You'll quickly burn those bridges when the other two realize you bought it through someone else and were just wasting their time all along.I'm on the side of quality over quantity in this case (which, ironically, is probably the root cause your original complaint).

If I were in your position, I would try to find the root cause of the problem... it could be the agent's management style or not.

@Scott FrenchIf you were selling an active business with a strong local brand - say a local market with deep roots in the community or a renown B&B - there would be a strong goodwill component (an intangible asset) and acquiring the business would be beneficial to the buyer.While this level of "brand" is theoretically possible in a local residential or commercial rental market, I've yet to encounter it in the wild.