There are of course (sneaky) ways to inspect the property without tenant being aware of the sale discussion (posing as insurance agent etc), however I do not want to run this business in a sneaky way, and even create a perception of being scam-y or sneaky with the customers... 

You then are attempt to acquire leads with "direct mail" and "driving for dollars".Direct Mail is a low return marketing channel, and the very best you can expect (even Kohl's, Vons, any local real estate broker) is a 1-3 percent return rate. 

We have been identifying properties with a big "spread" between the sold price from the Sheriff Sale and the ARV comps.  

I live in Inglewood and focus on Residential and Multi-Family sales.

With the deal (duplex), I am acquiring a tenant on the bottom floor.

What happens if: the rehab costs more than expected, the flip is delayed or the sales price is lower than expected?

The most useful information from either site is going to be past sales.

Once my client is completely ready to submit, I send over a full package to the other party including an the signed Purchase and Sale agreement, a copy of their pre-approval letter or proof of funds, a picture of the escrow deposit, a sheet explaining all of the comps that verify the offer price, and a brief explanation in the email as to what some of the terms are. 

My brother in law and I have been trying to purchase a rental for a few months now but we have been having trouble getting bids accepted.A few days ago we put in a bid on a short sale house last Friday.  

I usually create both a rental ad and a sale ad, both advertising the home as a lease option type of deal, in zillow rental manager (used to be postlets), which then syndicates to zillow, trulia, hotpads, aol, etc.