Mostly from a home equity line of credit.

Rate will be highly dependent on loan size, credit score, LTV, location, and property type, as well as a few other factors.

Any guidance or tips would be greatly appreciated!

It's likely a scam anytime they sound like AI or the grammar is weird or they use the word "kindly", if they ask for you to respond to them off-platform, if they say their employer will pay for it, if they ask if the dates they've specified are still open (when they can clearly see they are open on your calendar), if they ask for a video of your property (they probably want to set up a duplicate listing with your photos and video and scam others out of money), or if they want a long term booking and they have just joined the platform and have no reviews (could have been evicted from somewhere else, and hope a newbie will let them in with no background check, they'll end up not paying or credit card is bad).  

Huge thanks to Bo Stevens from Jean D'arc credit union, for helping me get a solid loan with a 6% interest rate with a super smoothe process.

Quote from @Jaycee Greene: Assuming you pay asking price, I'd estimate the down payment for something like that using a hard money loan (HML) would be around 40% of the purchase price and your monthly payment would be $2,600 with an interest rate in the low 7% range (probably need a 700+ credit score to get that).

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

Welcome to the community and be ready for a huge amount of information at your finger tips.

DM me and I'll connect you with the Credit Union I send my clients to.

I'd use an approved underlayment.Pro Tip: If it's cheap, it's not good.....at least spend in the moderate range.