Consider that when you hear someone say that you "have to" or "must" waive all protections/contingencies.

If you want it to be a long relationship that is the best way to protect both of you.

After that there may be other things (Insurance dept, consumer Protection if the Plumber C was licensed, ...)

The 1-2 punch of 1) discussion w/buyers agent 2) update client thing should come as naturally to you as shutting your front door after opening it - and for the same reason - to protect your hard earned assets.  

Second, note that certain states have more favorable laws when it comes to asset protection.

Protect your money by inspecting the property and using that report to renegotiate the price of the house or have the seller fix the issues!

These will protect you and make sure the work is being done to code.

Rentals owned via LLCs are strictly for liability protection and/or anonymity of ownership (in certain states).

I am wanting do this for both asset protection and tax purposes, but am pretty nervous about the whole lender issue.  

Now the S-corp and LLC are good routes to go with for protection but, with a S-corp can be difficult to form because I taken a accounting class recently and with s-corp are more regulated with striker laws by the IRS. which personal my final verdict goes to LLC because you are a single person in this business if I'm not mistaken which will get the job done with this option.