Without knowing the specifics of (1) your personal situation and (2) the particular property market conditions for the property market your property is located in and (3) the condition of your house, etc. it’s impossible for anyone to provide meaningful advice concerning whether or not to entertain this offer.Many states have standard contracts and procedures which have all but eliminated the need for an attorney when the sale of real property is done utilizing the “usual” methods of financing and ownership transfer.  

How long does it usually take to close one of these deals?

I don't get very creative with financing usually :-).

So we were able to get the meters brand new for $3,000 less than the new Electrician was going to charge us lowering our bill to $14,000 plus the cost of the meters $2400 which was extra from the labor anyway.

You don't necessarily have to create different LLCs for each properties, but if you have a large portfolio, usually they should be in multiple LLCs.

Prepayment penalties- usually 1-5 year terms.

If you dont need to use the extra cash, it's an added bonus/savings once the project is complete.

It depends on your level of experience and confidence in execution but usually relationships like this start with skin in the game from both parties to be fair to both sides. 

Lenders usually allow up to 8 draws. 

I prefer states that are landlord friendly - for example in Virginia you can evict for non-payment and usually get a judgement and possession in a few months.