If you own the land all the way to the lake, I would expect some basic signs, good insurance and perhaps a lifesaver on the shore would be sufficient. 

Your basic insurance policy with $300,000 in liability coverage should be sufficient in 99.999% of all lawsuits.5.

While we live in the area, our goal is to make these STRs as self-sufficient as possible so that 1) the cash flow they generate becomes increasingly passive, and 2) we feel confident investing in STRs out of state, which we’d like to do in the near future.

As a first-time investor/rehabber, with your hopefully very accurate rehab and ARV numbers indicating a sufficiently profitable project, you should potentially qualify for 75-80% financing on purchase (i.e. 20-25% down payment) and 100% financing on the rehab cost (funded to a reserve account and available in periodic post-expenditure draws). 

Certainly wouldn’t rely solely on an LLC to protect me without carrying sufficient liability insurance first. 

Perhaps some of the names mentioned here would be sufficient, but I was wondering if anyone could recommend a CRE attorney. 

I called my lender to get an updated pre-approval to send with my offer, and he told me it would not pass the self sufficiency test requirement for an FHA loan?

The state then investigates and determines if the complaint is "legally sufficient".

However, you should report that income anyways.If you want to buy a triplex or 4plex though, FHA will use what’s called the self-sufficiency test, and sometimes that will make it harder to qualify.

The reason is that FHA has something called a "self sufficiency test" for all 3-4 unit properties.