Not sure if they have upgraded to desktop appraisals but if they are still doing in person appraisals , make sure you get everything (scope of work, good faith deposit, social, LLC docs, insurance, proof of prior experience, financial statements) in ASAP.

@Tyler Speelman Your strategy to assist your sibling with a down payment while minimizing tax liability is creative but comes with complexities.

Proven Track Record – Experience in vacation rentals matters.

Quote from @Dyllon Gibbs: Hi All,Does anyone have experience with rent guarantee insurance and any specific companies?

You'll want to ask about their experience, read reviews, understand their availability, pricing, insurance / bonding, and how they safeguard their funds. 

You Get Experience"When the man with experience meets the man with money, the man with experience leaves with the money, and the man with the money leaves with an experience."

If they are the one providing most of the cash, they might not want to carry that liability, but you've already negotiated with your partners on this and then the bank isn't cool with it, you could be in a pickle.

Since you and your husband bring 20+ years of residential construction experience to the table, you already have a huge advantage.

I'm happy to share my experience with this market if you'd like to message me to set-up a call. 

I'd check local STR FB groups and see if you have a local Real Estate Club.You can offer your services there, maybe for free in exchange for the experience.