I  have to assume you value your license and keep people on the legal path, but you can understand that there is a difference between ethical and legal for "students".

I am wondering how do I go about finding ethical mentors in my area?

The more agents the firm has, the more rules will be set in place to keep that Brokerage out the ADRE's view, if issues arise with agents not doing business ethically or conflict of interest with their E/O insurance.    

But I also know REO's give preferential treatment to actual end users of their properties.

But the rehabs are well done, we average 3 to 5 maintenance calls per year, per unit.So i believe it subject to the maintenance, rehab/condition of the asset, background check of tenant, and relationship with the tenant.I believe the tenants treatment of the house is typically a reflection of the owners care of the property.

So I'd really appreciate suggestions from some of you who have personally worked with companies that are fair and ethical.

We are having an underground oil tank removed on one of our investment properties, for $2100.  How is this treated for tax purposes?  Unsure if it's considered an improvement to land in which case I would have to add ...

@Roy N. pointed out the agents ethical obligation to present offers.  

I know that the property must be listed on the open market and I want to avoid any ethical issues associated - any thoughts on the best way to handle purchasing this property at a lower price?

I'd then create a post on BiggerPockets saying where you are from and that you're looking for advice on how to find an ethical mentor in your area.