If we sell in bulk, it's a vetted process with brokers on the transaction and according to all local, state and federal rules.

In the scenario you have laid out- you will not be out of pocket any $ at the end of the transaction, and depending on the loan/closing costs, you will probably put a few thousand in your pocket. 

2) From the buyer's perspective who's solicited a seller to sell their property, who's real estate attorney or title co. should be used to carry out the transaction in the best interest of both parties?

There's a federal tax incentive:A taxpayer may claim a credit of 30% of qualified expenditures for a solar system that serves a residence located in the United States that is owned and used as a residence by the taxpayer.The LADWP (Los Angeles Department of Water & Power) also offers an incentive which comes in the form of a subsidy for the electricity you do get from the grid.

Not a lawyer, but I would have some concerns if I wasn't licensed and was involving your buyer in the transaction with their POF/Preapproval. 

Long story short, I excelled as a part time realtor and did more transactions than any other new agent in the office. 

Based on Revenue Procedure 2008-16, we recommend that our clients hold the property for investment for at least 24 months or more, to demonstrate that they have the intent to hold for investment.Once you have held the property for investment for at least 24 months, you can sell it and qualify for a combined 121 Exclusion and 1031 Exchange strategy.You would sell the property, exclude the full $500,000 in capital gains (as a married couple) from your taxable income, and complete a 1031 Exchange on the balance of the transaction to defer the rest of your capital gain, including any depreciation recapture, into the purchase of another rental property.

( here is how good transactions go down)  Most win and some lose its a investment and most can be controlled if you follow the correct processes ...  

I am waiting for the fire department report....this is such a headache LOL

I was talking to an escrow officer and she mentioned that doing assignments of contract or double closings requires one to have a license since they are considered real estate transactions.