I also appreciate the "reality check" tone of your message, as it can be easy to get excited and overly optimistic about new opportunities like this.I am new to CA MF RE, so I don't know a ton. 

She's going to need private financing (family, hard money lender, investor).Perhaps she could find an investor to loan the ~$125K to the ex and take (very high) interest only payments for a few years while she gets her finances in order.

This could be a huge lawsuit in and of itself.However, you have indicated to me that it is not your desire or intention to pursue any type of legal action against these people unless they double down and respond in the same negative tone to this response.

I know real estate isn't for the faint of heart & my skin is definitely in the game.

You missed my point.I think your point is that in a quiet residential street, even a single STR that’s poorly operated can feel disruptive and change the tone of the neighborhood.

Why he wants me to have some skin in the game when he's otherwise just going to give everything away I couldn't tell you.

You're likely going to need another $20-30k for make ready and furnishing expenses, though.

A couple of other things I’ve found valuable to look at are:Track record through cycles (how they’ve managed deals in both good and bad markets).Transparency and reporting (how proactive they are with communication, especially when things aren’t going perfectly).Alignment of interests (skin in the game, fee structure, co-investment).In my experience, those have been big predictors of how well a sponsor actually delivers in the long run.

Not just the “core 4” but actual partners who are both boots on the ground and have skin in the game. 

That is the "shelter" - no skin n the game, but you still get an expense.