I would add taxes to your list - got to watch out if the tax assessment or law changes with a change in ownership in certain cases / jurisdications

Also, if you have Propstream, pull a cash buyer list for the past two years and if you see that dozens of LLC's and simliar entities have bought homes, then you probably are fine.

Family #2 now needs to pay the taxes on the new assessed property tax (.73% avg) of the $1m.

Just out of curiosity and not challenging what your assessment of the uniqueness of the property, I'd like to know how the potential of it being unique earns more than having more sq ft to charge for?

I refuse to play that game.There are a dozen ways to split a water bill and require tenants to pay it in full each bill period.The same for gas, electric, cable, phone, or anything else.It helps if the lease states the obvious responsibilities along with repercussions when the lease is NOT followed to the letter.This may take an actual attorney to help you write this into your lease, and it may cost to have your attorney effect the discipline required by said lease.Just save that talk saying there is nothing you can do but change toilets, faucets, and make sudden inspections.

i would get several more quotes in, preferably from people who fix stuff, not up-sell you on stuff you might not need. i would make sure the crawl space is/stays dry then assess what the best course of action is. since you'll have tenants in there, i doubt they care where their air is coming from (floor or ceiling). why waste $16k if other options could be available?

That said, I don't hear many stories about folks building STRs from scratch.Has anyone done it that can share how they assessed value/risks?

@Diana Costta I should have said the assessed value increased 30%. 

@Ken BooneAgree with that assessment, it’s definitely a shake my head situation.

Have a plumber do an assessment and get their conclusion in writing as evidence that you did your part as a landlord.