Long story short, my wife and I made a very poor decision going into real estate/landlording with my sister in law and we want out.

Ask for their feedback on what it would likely take for you to get a loan on those sample properties.Remember that unless you're paying cash, the real decision maker on deals is the lender.

Include how much money is being invested by your friend (downpayment and the fix & flip costs) who will be managing the project, who will be making key decisions, who is doing each segment of the renovations and spell out specifically all the costs for the flip - including: Money for renovations, taxes, insurance, and loan payments while they own the house, utilities, marketing the property for sale & the agent’s commission - if using a R.E. agent.

I would look long term to make my decision. 

The key is to find good investments (not scams) that don't require your direct involvement to be successful (other than certain managerial or decision-making input).

You will have to make the decision if you want a portfolio loan or each individual property loan.

Although, agents will claim that they have worked with investors, how do you really know which ones have the capability to guide you in making the right decision when purchasing your investment property?

We like markets that are friendly to short-term rentals and I know that will be a big part of our decision-making process with future areas we invest in.Do you have a way of determining markets you want to invest in?

Just be careful here as you need to comply with neighborhood CC&Rs as well as city codes.Talk to multiple realtors to see if any of them have any "pocket listings" or know anyone who is considering selling, but hasn't made the decision to list. 

I hope that decision comes soon.