Are you finding your investors are happy to let their investment ride throughout the life/time of ownership that you as the proprietor keep the property? 

I don't think there is anything you technically need to start, I don't believe you even need an LLC to get started you could just work as a sole proprietor when starting out.

You are in business, you are simply operating as a "Sole Proprietor" Yes your expenses are deductible.

The articles talk about the difference between the basic choices you have: (1) sole proprietor/partnership; (2) S-Corp; and (3) C-Corp.

If you set up an LLC with only you and your husband as members (a single member by virtue of your joint tax return) and that LLC chooses to be taxed as a sole proprietor then it is what would be called a disregarded entity. 

Next, I think I need to set up an LLC, and I say I think I need to set up an LLC, because there's also S Corp, C Corp, Sole Proprietor and maybe more that I don't know about.

If your just a self proprietor for RE investing  it’s actually very simple 

@Nancy Zhao I am wondering more about how much the SC taxes would be if we live-in flip vs. being a sole proprietor after we sell.

Not sure about your question.....The person who is doing the wholesaling needs to determine if they should be doing business as a sole proprietor or with an LLC......once again question for there accountant. 

The sole-proprietor LLC will be pass through for tax purpose anyway at the end of the year.