Having said that, you should pay your brother a fair price for his services.I have done multiple projects where I was the GC on joint ventures and always charge a fair market price. 

@Evan AagaardI have heard if you add the investor A (that is on title for house and mortgage ) to a joint account w investor Bs money in it - then investor A can show he has access to full 20% down.

My solution was to ask the wholesaler to partner with us and help us convince the owner to "joint venture" with us on the project.

But you still don't have the ability to underwrite the individual assets in advance.The third type of fund is a joint venture fund. 

Even if they didn’t want to sell they could spread the word, and I can cultivate some genuine relationships in the neighborhood and build a good reputation.

If you wait until you are married the property will be on your joint tax return so you'll both be owners anyway and you'll become what we call "accidental investors". 

To prevent the issue from arising we emphasize the "joint and severally liable" clause in the lease, which means all the tenants are collectively responsible for the lease. 

Additionally, would you recommend a qualified joint venture (QJV) or partnership versus sole proprietorships?

Disrespect , sarcasm. and anything but genuine helpful answers are not welcomed.

Look into "Joint Venture" agreements perhaps!