I have not looked for any wording saying one must complete a new lease ...my colleagues have told me they have automatic renewal clauses (not month-to-month, but annual) and they merely send notice of a rent increase.

The site merely provides leads that you need to thoroughly vet as you should with all contractors.

The challenge with these types of properties is merely because the home owner signs the agreement of sale, that does not mean you have a deal because it is subject to lender approval which can take months, tons of frustrating paperwork and, even then, the lender may not approve the sale.

Having an attorney who also invests in real estate can often offer a lot of value that goes beyond mere legal advice. 

4) Can a landlord, upon expiration of a lease merely state that they no longer want to rent it to the tenant for any explanation given?

You may want to check out our website, www.LogicalPM.com, because unlike our competitors who MERELY state what they can do for you, we provide an outline of how we execute each of the services we provide!

To be honest, that post made me re-evaluate my plans to sell some of my Los Angeles properties.

But in the situations I've had, the mere threat of bringing the attorneys into it--or in one case having the attorney write them a letter--resolved the issue pretty fast. 

Agree with @Lance LvovskyFirst we'd need to know if rental real estate is a 'trade or business' for you or merely an 'investment'. 

I am not at all saying that your way is wrong and mine is right.With that said, I was merely pointing out that a self directed IRA or 401k owner must be aware of all the IRS guidelines regarding buy and hold RE and be careful not to violate any.