With what you are trying to do, there may be some structures we can come up with in order to avoid the securities world, but would need to dig into detail.  

Depending on if each of the family members are interested to do their own deals with you or you are combing the money into one fund and purchasing a property, there can be different structures. 

If a seller has a property free and clear how do you structure a seller financing in order to not get a bank loan??

@Ronald Daley - you mean a structural engineer?

We are looking to formalize our business into an appropriate entity structure (recommendations for a local attorney are definitely welcome!)

By structuring the transaction this way, the buyer will not have to put down any of their own money to buy/close. 

From my understanding, the benefits of having an LLC are going to come into play most often for structuring partnership deals and litigation arising from issues on the property.

In most standard policies the insurance company will provide an additional 10% of the dwelling amount for "other structures".

I am looking for some legal advise to determine my business structure in the US.

It also includes regulation A offerings inside of the tier 1 and tier 2 fund structures.