Non-disclosure of expensive problem with new house

Location: Minnesota

Bought a new house that has a geothermal heating and cooling system. One of the main reasons we chose this place…

Long story short, there is a leak in the in-ground loop system (and other problems) with the system….

I called the hvac company they used and got the service records for the house it’s a mile long; previous owner had been having lots of problems with the system and frequently declined the repairs the hvac company would recommend.. In fact, this company was at our house 3 days before closing for a leak (owner decline to fix) and to re-pressurize the loops (different leak) before we purchased…. None of the disclosed on sellers disclosure.

Obviously I need an attorney and I spoke to one .. he basically gave me 3 options.

1. He can ghost write a “shake down” letter for me to send just to kind of get a sense of how the previous owner will respond

2. he can send demand letter on firm letter head

3. file lawsuit

Can also do nothing or try conciliatory court ($20k max)..

Lots of different ways to calculate damages but this geo system is completely fucked and without the tax credits it’s hard to justify replacing and not just putting in a regular furnace/ac.. which would completely change the value of the house and the energy costs each month.

Does anyone have a strong preference on 1 of the 3 options above? Do you feel this rises to the level of consumer fraud ? Thanks in advance.