Sounds like they'll be providing bids with essentially zero opportunity of ever getting the work (or getting paid).I know you probably think you'll pass the bids on to your end-buyer so your end-buyer may use the contractor, but in reality, serious end-buyers will have their own contractors and will generate their own repair estimates.

As a homeowner I have gotten letters from the town essentially saying we noticed a hole in your yard - you are not doing anything we didn't permit..  

Any changes in procedure, paperwork, restrictions I should be aware of?

(Possibly these last three might be different versions of essentially the same thing)

Is there any type of paperwork required (i.e. registering my business license in the Inland Empire since it's a different county) in order to start collecting rental income? 

The paper work is there not for when things go well, but for when things go bad.Good luck,Oren

It's essentially a pretty hefty text book, with about 25 chapters that you'll jump around through based on the curriculum they tell you to follow.

Like for instance a "temporary moratorium" on payments.Study up on annuities, as home sellers are essentially taking their equity in installments. 

There is some minor paperwork involved and periodic inspections.

You are essentially looking for the intersection of four factors:1.