I looked into getting pre-qualified for a loan, but my W-2 and our business doesn't show enough income to make lenders feel comfortable.

When I started I found that I did a better job understanding  analyzing better when I worked out the deals myself that helped me get comfortable with numbers based on what I sought as a return.  

I've long loved the construction side of my job as an interior designer and I've spent most of my career creating spaces to either make people feel immediately at home (hotels and restaurants) or where they WANT to be home (multifamily & builder models).  

Increase your volume of offers, broaden your buyer list, and you will be in a much more comfortable position.  

The prop would be in an Llc with both our names but I'm thinking I would only be on the lone and I'm not comfortable with that.

Never got the CPA designation as I can do the same things with the law license.

If a seller won't give you any actual tax info are alternate verification of expenses I would take it as a red flag.For a new investor I would want to be very comfortable with knowing my units would be in demand.  

Conceivably, these siblings would either list and sell the asset to your investor (for which you receive commission #1) or you bring in a developer/syndicator.In the second scenario, siblings would partner up and contribute their equity into the formal or informal partnership and the developer/syndicator would bring experience (successful track record), and other resources including builders, design architects, engineers, and entitlement experts for zoning and building approval, depending in the scale of the project.A third choice exists whereby siblings attempt development themselves.

For non emergency you could designate one day of the week to address  problems and do it all on one day letting the tenant know what day you will be out

If you are in a good market for flips and feel comfortable with that as your first strategy go for it.