Sounds like you have many speculative ideas with many unknowns and many risks.

Ultimately, I believe this comes down to, I need 250K for the down payment at a 5ish % to make this work, but I‘m so new the unknowns are holding me back.

At the end of the day, the due diligence process is meant to determine if there are unknown issues and whether its still the deal you thought originally.

As of now, the tax rate is unknown, so your taxes are unknown.What you need to do is appeal/protest the assessed value.

We completed an extensive remodel on two houses and got it listed with this person.The property was supposed to be listed on a Monday, unknown to us the agent went out to state to party with some friends and was too drunk to list it until Thursday or Friday.

Construction and renovation are never going to go perfect, it is the nature of the unknown - but communicating what's going on seems to be difficult for most GCs.I would be very aware of the payments you've made and be sure not to overpay - that is really your only leverage. 

This story is HUGE but I'll try to keep it brief.June 2019 a woman signs a 12 month contract that says she must get electric and gas in her own name prior to move it and no one except her can occupy the unit (she breaks all 3 of those)Unknown to me - the man now squatting moves in with the former tenantJuly 20, 2020 she suddenly has a huge amount of cash and pays over 5 months back rent - never pays rent again after this dayJuly 23, 2020 booked for a crimeFeb 2020 person moves into cabin next door and somehow put wrong cabin electric meter in their nameNov, 2020 she's jailedMay 2021 my dad arrives and slowly starts realizing the scope of the problemJuly 2, 2021 I arriveJuly we get Real Estate One to be property managers starting Aug 1, REO agent meets with 2 current tenants and gets them on new contracts, REO makes a deal with squatter, he agrees, he never shows up to the REO officeAug 9 post 7 day notice due to non paymentAug 16 court house says can't because COVID, try 30 day notice to quit - post thatAug 17 hand 30 day notice to quit to squatter (had to bang on his door at 7:15a to catch him as he'd been hiding from me for 2 weeks)Aug 19 figure out squatter's cable is in the name of jailed tenant's daughter who lives 2 counties away with her legal guardian (yet Spectrum refuses to cancel service)Aug 20 figure out the electric meter mix up. next door unit moved out in June yet was still be charged electric. why?

There will always be more risk and wear on a short term rental with unknown weekly tenants and potential profit must match the risk I vet my tenants very thoroughly.

- How do I get comfortable with unforeseen risks (sewer problems, unknown foundation issue, roof etc) that ay come up once I crack into the walls?

Always try to be a few moves ahead so you have room for the unknown.