With that said, cash is the more common first step because many properties with the most BRRRR potential are not in good enough condition for a bank to approve a traditional mortgage on in the first place.

In the very common event of interstate exchanges it is many times a requirement that the new property be owned in a domestic LLC to that state. 

@Christian WeberTo answer a few of your questions,If the property will be vacant for more than 60 days, then you will want to go with a Vacant Building or Builders risk policy depending on the rehab detailsPersonal Umbrella policies can get picky going over out of state or vacant buildings.The most common limit for General Liability is $1M. 

TriplexLive in one and rent the other two.Almost rent free.Tenants pay my mortgage, taxes and....Helps to be a common sense do it yourself type of person.

The only way to speculate an addition based flip would be if you’ve built several and “see” what may or may not be similar to comparable projects, and even then you need margins for significant error.

Bob has understood the deep, deep error of his ways in having let Marcus live with him in the past.

If you do decide to go with working with each other.There are two ways for multiple people to own property - Tenants in Common(TIC) or through an entity(Corp, LP, LLC, etc)Best of luck!

Again, check the laws of your state about deposits and see what is common.

What I've done is if there is interest I just send them a message with everything including answering common questions.  

Are there any errors I can make with doing so?