You may want to request the construction drawings / plans for the utilities that were installed to help better understand their impact to your property. 

So I got a quote from a local construction company to convert the garage into an ADU, and they said 90k - 125k, probably toward the high end of that range. 125k.

consulting  a civil right attorney is probably your best bet.

My oldest child is going to college next year in a town where I could buy a house for $160k. I've got the cash to buy it outright, then let him live there, rent out the other bedrooms to classmates, etc. And ideally s...

If he doesn't do biz structure or contracts,  I bet he'll have referrals.  

A study by Geraci LLP, analyzing data from 125 lending companies, shows that the private lending industry performed significantly better in the first four months of 2024 compared to the same period in 2023.When it comes to short-term loans—like fix-and-flip, construction, and bridge loans—there was a notable increase in production from 2023 to 2024.

I put some numbers below into this Rent or Sell calculator.https://www.narpm.org/members/resources/rent-vs-sell-calculator/ESTIMATES ON ROI (15 year time frame)at 5% Appreciation would profit $100K if SELL nowat 6% Appreciation would have $3,500K more if KEEP and sell after 15 yearsat 7% Appreciation would profit 122K if KEEP and sell after 15 years(Assuming a conservative 6% ROI on money invested from sale.)NOTE: The property appreciated 10% in the last year so I’m thinking 7% over the next 10-15 is reasonable.DETAILSSale Value: $520,000 (Best guess)Paid: $437,000Original Mortgage: $415,000Mortgage Balance: $380,000Interest: 3.375%Monthly mortgage: $2,899Mortgage Difference: $1064Annual Taxes, Insurance, HOA etc**: $20,345**$13,865 (Non Homestead tax) $4,680 (HOA) $1,800 (Landlord Insurance)Monthly Rental Charge $3,500*Appreciation 7%Years to Hold: 15More assumptions used in ROI Estimates Above90% occupancy,15% capital gains charge6% selling feeRate of return on gains if selling now instead 6%Annual maintenance 1%Annual rent increase 4%$3,500 is slightly aggressive. unlikely I could get more.Thanks in advance for any constructive thoughts and comments!!!!

At the time that we signed, Ryan and his construction manager estimated that the project would take about 3 months.

I think being an inspector is a great way to learn more about property and construction, but it's not a direct path to becoming an investor. 

Again, being very focused on key buildings close to new constructions being delivered in 2-4 years, in key growth areas, you can get good deals and cash in apprecitation in the mid-long run.In older buildings, if you are not financially solid, it's recommended to sell before HOA and Special Assessment will put you out of business.