if they ever default on their payments, and it goes to a judge, they will say that they are an owner not a tenant. 

Own 3 LTR properties all in CA under a Trust.3.

Trust me, I've toyed with the idea.Vacant land where it makes sense to build large MFH stock might make sense, but chances are this isn't the land we're talking about here.The reality is most vacant land in Detroit is being repurposed for parks, the Joe Luis Greenway, solar farms, neighborhood gardens, etc.Beyond that, let's say you plan to hold long enough for SFH prices to get high enough where it does make sense to build. 

They contributed $125,000 cash as the down payment (25% of purchase price) but my wife and I are the only individuals on the mortgage loan.  

ACH and debit/credit card payments are usually a couple days.

If you buy in with a high rate, wait two years, and your property appreciates and rates come down, you get a double windfall when you refi because the payment goes way down and you have equity to pull.BUT, that is a big if in today's market.

One of the city's structural engineers actually told me I could hire a drafter if my budget is under 30K and trust and believe it IS!

The borrower is coming in with only 10% of the down payment if approved.

We did this all ourselves with our own funds for down payments. 

@Karthik NatarajanProps to you for doing your due diligence.In many areas, assessment amounts are adjusted upon sale of the property so it is NOT unusual and in fact it is quite common for property taxes to increase significantly for a new buyer.Absent any other data, I’d trust the calculator.You could also call the County Tax Collector or Asssesor to verify the information.Good luck.Arn