In Escrow, Mold Found- Walk or Remediate?

In escrow for first home $1m+ in Southern California- further below is a very concise summary of what’s going on. The below findings were concerning the family room, garage, dining room and master bedroom. It’s a flip of a 1970s home. Seller has agreed to locate source and fix it, allowing us to find the remediation company and then have independent testing clearance done afterwards. Love the house, a lot. Obvious concern of future issues. Also the first buyer backed out due to a qualification issue apparently & we stepped in beating out their secondary buyer they went to.

Any advice of anyone that’s been in this position before would be appreciated. Should I walk or give it a shot? What would you do??

The inspection found elevated moisture and mold/spore activity, indicating possible ongoing water intrusion behind walls or flooring.
Possible causes include:
Poor drainage/grading
Blocked weep screeds
Missing gutters/downspouts
Leaky windows
Stucco waterproofing issues
Shower leaks