I typically spend up to 20% of my commissions on lead generation online and off.

Show separately for 2017 and the 3 preceding years: gross sales, cost of goods sold, gross profit, percentage of gross profit to gross sales, amounts collected, and gross profit on amounts collected.It seems, after reading this, that your solution would be the correct one - enter the gross profit for each year on Line 1 of Schedule C with a separate statement attached to the return describing the installment sale and how you arrived at the gross profit. 

Do I list them as an operating expense on schedule E even though they occurred before the in service date?

Dating?

You will have to go through probate with an attorney to transfer title, unless property is in a trust, or if property is appraised under 150K, at the date of death, you can do a terms of succession, which is usually a few months instead of a whole probate process and if there are multiple heirs it gets tricky.

I head about them online, however their terms & condition paper work does not look very common and has multiple confusing clauses.Just want to know if anyone knows about them or their service?

I  go to these things to gain a little bit of information if any, but I see no reason to go to the paid ones since I can get the information I need via online like Bigger Pockets. 

Note: a Mortgage Credit Report will pick up dirt that those worthless "Online" consumer fico score reports won't show.Depending on how much of a Credit Criminal you have on your hands, in addition to a substantial "refundable deposit ask for 1st month's and last 2 month's rent up front (note: need to open an escrow account to deposit the rent payments and deposit collected)Write lease with an "EPD"  (Early Payment Discount), meaning if they ensure that you receive the monthly payment BEFORE the 1st day of the month, the rent is discounted $50, $100, $300 or whatever, depending on if you are leasing out a $50k home or a $3,000,000 home.And the very first time the rent is 5 days late, hire an evection company to go post an eviction notice to start the process and/or show them you are not playing and they will likely ensure you receive the rest of the rents on time after thatAnd I could go on and on listing things to do, but these are a few good ones  

What do I still need to do due diligence wise and should I give up on trying to contact the LLC before auction date?

I would suggest looking at some rental listings in greenville online.