What is the best way to structure it?

I Was pitched an IRA/LLC structure where the SDIRA was 51% and Iowned the other 49%.supposedly this was not prohibited.

As far as your structure, it would be better to have the two investors enter into an LLC as a partnership, with their own operating agreement done up by an attorney.

Now, I just have to figure out a deal structure for our meeting tomorrow.

I have a family friend that is loaning me some money to do a flip, but I don't know how to structure the paperwork for the loan.

If it is determine that you really own the property through your LLC and your silent partner has no ownership interest in the property, you could probably structure a 1031 Exchange whereby you acquire your partner's primary residence as long as you convert the property immediately into rental/investment use. 

I have a family friend that is loaning me some money to do a flip, but I don't know how to structure the paperwork for the loan.

Is there anyway to structure this deal in this situation?

If your business entities and trust(s) are properly structured, your history as a past owner does not have an impact when someone is seeking to find the human behind the owner(s) of any specific property, as far as I know.

A master at deal structuring/transactioneering.